diff --git a/build.gradle.kts b/build.gradle.kts
index 23c2caf..2526b41 100644
--- a/build.gradle.kts
+++ b/build.gradle.kts
@@ -3,7 +3,7 @@ import java.time.format.DateTimeFormatter
 import org.gradle.jvm.toolchain.JavaLanguageVersion
 
 plugins {
-	id("dev.isxander.modstitch.base") version "0.8.4"
+	id("dev.isxander.modstitch.base") version "0.8.5"
 	id("com.modrinth.minotaur") version "2.+"
 }
 
@@ -84,6 +84,12 @@ stonecutter {
 		"forge" to loader.equals("forge", ignoreCase = true),
 		"vanilla" to loader.equals("vanilla", ignoreCase = true),
 		"mc26" to (minecraft == "26.1.2"),
+		// TraderHighlightRenderer: MC 26 uses Fabric LevelRenderEvents; 1.21.x uses WorldRenderEvents (v1.world).
+		"traderWireframeRender" to (minecraft == "26.1.2" || minecraft == "1.21.11" || minecraft == "1.21.10"),
+		"traderWireframeMc26" to (minecraft == "26.1.2"),
+		"traderWireframe121" to (minecraft == "1.21.10" || minecraft == "1.21.11"),
+		"traderWireframe12110" to (minecraft == "1.21.10"),
+		"traderWireframe12111" to (minecraft == "1.21.11"),
 		"npcSplit" to (minecraft == "26.1.2" || minecraft == "1.21.11"),
 		"npcFlat" to (minecraft == "1.21.10"),
 	)
diff --git a/src/main/java/com/github/sebseb7/autotrade/event/AutoTradeClientTick.java b/src/main/java/com/github/sebseb7/autotrade/event/AutoTradeClientTick.java
index 9d9a01c..442ea89 100644
--- a/src/main/java/com/github/sebseb7/autotrade/event/AutoTradeClientTick.java
+++ b/src/main/java/com/github/sebseb7/autotrade/event/AutoTradeClientTick.java
@@ -11,6 +11,7 @@ import java.util.List;
 import java.util.Vector;
 import net.minecraft.client.Minecraft;
 import net.minecraft.client.gui.screens.inventory.ContainerScreen;
+import net.minecraft.network.chat.Component;
 import net.minecraft.client.gui.screens.inventory.MerchantScreen;
 import net.minecraft.client.gui.screens.inventory.ShulkerBoxScreen;
 import net.minecraft.core.BlockPos;
@@ -48,7 +49,6 @@ final class AutoTradeClientTick {
 	private final Vector<Entity> villagersInRange = new Vector<>();
 	private int villagerActive = 0;
 
-	private boolean state = false;
 	private boolean inputInRange = false;
 	private boolean inputOpened = false;
 	private boolean outputInRange = false;
@@ -68,6 +68,7 @@ final class AutoTradeClientTick {
 
 	private int inputContainerHighlightTicks = 0;
 	private int outputContainerHighlightTicks = 0;
+	private int postMerchantInventorySyncTicks = 0;
 
 	/**
 	 * Entity to draw in-world highlight for; {@code null} when inactive or unknown
@@ -102,7 +103,14 @@ final class AutoTradeClientTick {
 		if (containerDelay > 0) {
 			containerDelay--;
 		}
-		if (!Configs.Generic.ENABLED.getBooleanValue() || mc.player == null) {
+		if (mc.player == null) {
+			return;
+		}
+		if (postMerchantInventorySyncTicks > 0) {
+			postMerchantInventorySyncTicks--;
+			ContainerIoHelper.syncPlayerInventoryAfterMerchant(mc);
+		}
+		if (!Configs.Generic.ENABLED.getBooleanValue()) {
 			return;
 		}
 		Inventory plInv = mc.player.getInventory();
@@ -158,9 +166,9 @@ final class AutoTradeClientTick {
 							//?} else {
 							mc.gameMode.interact(mc.player, entity, InteractionHand.MAIN_HAND);
 							//?}
+							postMerchantInventorySyncTicks = 0;
 							voidDelay = Configs.Generic.VOID_TRADING_DELAY.getIntegerValue();
 							villagerActive = entity.getId();
-							state = false;
 							break;
 						}
 					}
@@ -296,64 +304,101 @@ final class AutoTradeClientTick {
 	}
 
 	private void tickMerchantScreen(Minecraft mc, MerchantScreen screen) {
-		if (!state) {
-			String sellItemStr = Configs.Generic.SELL_ITEM.getStringValue();
-			String buyItemStr = Configs.Generic.BUY_ITEM.getStringValue();
-			state = true;
-			MerchantMenu menu = screen.getMenu();
-			MerchantOffers offers = menu.getOffers();
+		MerchantMenu menu = screen.getMenu();
+		MerchantOffers offers = menu.getOffers();
 
-			// Cache offers for the in-world trade overlay.
-			Entity activeEntity = findEntityById(mc, villagerActive);
-			if (activeEntity != null && offers != null && !offers.isEmpty()) {
-				VillagerTradeCache.put(activeEntity.getUUID(), offers);
-			}
-			for (int i = 0; i < offers.size(); i++) {
-				MerchantOffer offer = offers.get(i);
-				int tradesLeft = offer.getMaxUses() - offer.getUses();
-				if (TradeItemSpec.matches(offer.getResult(), buyItemStr) && Configs.Generic.ENABLE_BUY.getBooleanValue()
-						&& offer.getResult().getCount() <= Configs.Generic.BUY_LIMIT.getIntegerValue()) {
-					if (tradesLeft > 0 && playerHasMerchantCosts(mc.player, offer)) {
-						Slot slot = menu.getSlot(2);
-						menu.setSelectionHint(i);
-						mc.player.connection.send(new ServerboundSelectTradePacket(i));
-						AutoTrade.bought += offer.getMaxUses();
-						InfoUtils.showGuiOrInGameMessage(Message.MessageType.INFO, "autotrade.message.trade_bought",
-								formatItemCountNameForTrades(offer.getResult(), tradesLeft),
-								formatOfferPriceForTrades(offer, tradesLeft));
-						try {
-							ContainerIoHelper.quickMoveResultSlot(mc, menu, slot.index);
-						} catch (Exception e) {
-							System.out.println("err " + e);
-						}
+		Entity activeEntity = findEntityById(mc, villagerActive);
+		if (activeEntity != null && offers != null && !offers.isEmpty()) {
+			VillagerTradeCache.put(activeEntity.getUUID(), offers);
+		}
+
+		if (tryExecuteOneMerchantTrade(mc, screen)) {
+			ContainerIoHelper.syncPlayerInventoryAfterMerchant(mc);
+			return;
+		}
+
+		finishMerchantSession(mc, screen);
+	}
+
+	/**
+	 * Runs at most <strong>one</strong> trade per tick so the server can answer before the next
+	 * packet — avoids inventory slot ghosts from batched select-trade + shift-clicks.
+	 */
+	private boolean tryExecuteOneMerchantTrade(Minecraft mc, MerchantScreen screen) {
+		MerchantMenu menu = screen.getMenu();
+		MerchantOffers offers = menu.getOffers();
+		if (offers == null || offers.isEmpty()) {
+			return false;
+		}
+		String sellItemStr = Configs.Generic.SELL_ITEM.getStringValue();
+		String buyItemStr = Configs.Generic.BUY_ITEM.getStringValue();
+
+		for (int i = 0; i < offers.size(); i++) {
+			MerchantOffer offer = offers.get(i);
+			int tradesLeft = offer.getMaxUses() - offer.getUses();
+
+			if (TradeItemSpec.matches(offer.getResult(), buyItemStr) && Configs.Generic.ENABLE_BUY.getBooleanValue()
+					&& offer.getResult().getCount() <= Configs.Generic.BUY_LIMIT.getIntegerValue()) {
+				if (tradesLeft > 0 && playerHasMerchantCosts(mc.player, offer)) {
+					Slot slot = menu.getSlot(2);
+					menu.setSelectionHint(i);
+					mc.player.connection.send(new ServerboundSelectTradePacket(i));
+					AutoTrade.bought += offer.getMaxUses();
+					showTradeNotice(mc, "autotrade.message.trade_bought",
+							Component.literal(formatItemCountNameForTrades(offer.getResult(), tradesLeft)),
+							Component.literal(formatOfferPriceForTrades(offer, tradesLeft)));
+					try {
+						ContainerIoHelper.quickMoveResultSlot(mc, menu, slot.index);
+					} catch (Exception e) {
+						System.out.println("err " + e);
 					}
+					return true;
 				}
-				if (TradeItemSpec.matches(offer.getCostA(), sellItemStr)
-						&& Configs.Generic.ENABLE_SELL.getBooleanValue()
-						&& offer.getCostA().getCount() <= Configs.Generic.SELL_LIMIT.getIntegerValue()) {
-					if (tradesLeft > 0 && playerHasMerchantCosts(mc.player, offer)) {
-						Slot slot = menu.getSlot(2);
-						menu.setSelectionHint(i);
-						AutoTrade.sold += offer.getMaxUses();
-						mc.player.connection.send(new ServerboundSelectTradePacket(i));
-						InfoUtils.showGuiOrInGameMessage(Message.MessageType.INFO, "autotrade.message.trade_sold",
-								formatItemCountNameForTrades(offer.getCostA(), tradesLeft)
-										+ formatOptionalSecondCostForTrades(offer, tradesLeft),
-								formatItemCountNameForTrades(offer.getResult(), tradesLeft));
-						try {
-							ContainerIoHelper.quickMoveResultSlot(mc, menu, slot.index);
-						} catch (Exception e) {
-							System.out.println("err " + e);
-						}
+			}
+
+			if (TradeItemSpec.matches(offer.getCostA(), sellItemStr)
+					&& Configs.Generic.ENABLE_SELL.getBooleanValue()
+					&& offer.getCostA().getCount() <= Configs.Generic.SELL_LIMIT.getIntegerValue()) {
+				if (tradesLeft > 0 && playerHasMerchantCosts(mc.player, offer)) {
+					Slot slot = menu.getSlot(2);
+					menu.setSelectionHint(i);
+					mc.player.connection.send(new ServerboundSelectTradePacket(i));
+					AutoTrade.sold += offer.getMaxUses();
+					showTradeNotice(mc, "autotrade.message.trade_sold",
+							Component.literal(formatItemCountNameForTrades(offer.getCostA(), tradesLeft)
+									+ formatOptionalSecondCostForTrades(offer, tradesLeft)),
+							Component.literal(formatItemCountNameForTrades(offer.getResult(), tradesLeft)));
+					try {
+						ContainerIoHelper.quickMoveResultSlot(mc, menu, slot.index);
+					} catch (Exception e) {
+						System.out.println("err " + e);
 					}
+					return true;
 				}
 			}
 		}
+		return false;
+	}
+
+	private void finishMerchantSession(Minecraft mc, MerchantScreen screen) {
+		ContainerIoHelper.syncPlayerInventoryAfterMerchant(mc);
 		screen.onClose();
 		ContainerIoHelper.syncPlayerInventoryAfterMerchant(mc);
+		postMerchantInventorySyncTicks = 15;
 		startTraderGlow(mc, villagerActive);
 	}
 
+	/**
+	 * Malilib's {@code showGuiOrInGameMessage} routes to multiple HUD targets; trade spam looked like 3× duplication.
+	 * Vanilla overlay is a single on-screen line (same idea as vanilla toast-adjacent hints).
+	 */
+	private static void showTradeNotice(Minecraft mc, String translationKey, Component arg1, Component arg2) {
+		if (mc.gui == null) {
+			return;
+		}
+		mc.gui.setOverlayMessage(Component.translatable(translationKey, arg1, arg2), false);
+	}
+
 	private void tickTraderGlow(Minecraft mc) {
 		if (mc.level == null || traderGlowTicksRemaining <= 0) {
 			return;
diff --git a/src/main/java/com/github/sebseb7/autotrade/render/TraderHighlightRenderer.java b/src/main/java/com/github/sebseb7/autotrade/render/TraderHighlightRenderer.java
index e59b92b..e48d054 100644
--- a/src/main/java/com/github/sebseb7/autotrade/render/TraderHighlightRenderer.java
+++ b/src/main/java/com/github/sebseb7/autotrade/render/TraderHighlightRenderer.java
@@ -1,16 +1,13 @@
 package com.github.sebseb7.autotrade.render;
 
-//? if mc26 {
+//? if traderWireframeRender {
 import com.github.sebseb7.autotrade.config.Configs;
 import com.github.sebseb7.autotrade.event.KeybindCallbacks;
 import com.mojang.blaze3d.vertex.PoseStack;
 import com.mojang.blaze3d.vertex.VertexConsumer;
-import net.fabricmc.fabric.api.client.rendering.v1.level.LevelRenderContext;
-import net.fabricmc.fabric.api.client.rendering.v1.level.LevelRenderEvents;
 import net.minecraft.client.Minecraft;
 import net.minecraft.client.renderer.MultiBufferSource;
 import net.minecraft.client.renderer.ShapeRenderer;
-import net.minecraft.client.renderer.rendertype.RenderTypes;
 import net.minecraft.core.BlockPos;
 import net.minecraft.util.Mth;
 import net.minecraft.world.entity.Entity;
@@ -18,6 +15,20 @@ import net.minecraft.world.phys.AABB;
 import net.minecraft.world.phys.Vec3;
 import net.minecraft.world.phys.shapes.Shapes;
 //?}
+//? if traderWireframeMc26 {
+import net.fabricmc.fabric.api.client.rendering.v1.level.LevelRenderContext;
+import net.fabricmc.fabric.api.client.rendering.v1.level.LevelRenderEvents;
+//?}
+//? if traderWireframe121 {
+import net.fabricmc.fabric.api.client.rendering.v1.world.WorldRenderContext;
+import net.fabricmc.fabric.api.client.rendering.v1.world.WorldRenderEvents;
+//?}
+//? if traderWireframe12110 {
+import net.minecraft.client.renderer.RenderType;
+//?}
+//? if traderWireframeMc26 || traderWireframe12111 {
+import net.minecraft.client.renderer.rendertype.RenderTypes;
+//?}
 
 /**
  * Client wireframe highlights: last-traded villager, and input/output container
@@ -30,21 +41,27 @@ public final class TraderHighlightRenderer {
 	}
 
 	public static void register() {
-		//? if mc26 {
-		LevelRenderEvents.AFTER_SOLID_FEATURES.register(TraderHighlightRenderer::renderLevel);
+		//? if traderWireframeMc26 {
+		LevelRenderEvents.AFTER_SOLID_FEATURES.register(TraderHighlightRenderer::renderLevelMc26);
+		//?}
+		//? if traderWireframe121 {
+		WorldRenderEvents.END_MAIN.register(TraderHighlightRenderer::renderWorld121);
 		//?}
 	}
 
-	//? if mc26 {
+	//? if traderWireframeRender {
 	private static final ShapeRenderer SHAPE_RENDERER = new ShapeRenderer();
 
 	private static final int TRADER_OUTLINE_COLOR = 0xFF66FF66;
 	private static final int INPUT_CONTAINER_COLOR = 0xFFFF6666;
 	private static final int OUTPUT_CONTAINER_COLOR = 0xFF6666FF;
 
+	//? if traderWireframeMc26 || traderWireframe12111 {
 	private static final float LINE_WIDTH = 2.5F;
+	//?}
 
-	private static void renderLevel(LevelRenderContext context) {
+	//? if traderWireframeMc26 {
+	private static void renderLevelMc26(LevelRenderContext context) {
 		Minecraft mc = Minecraft.getInstance();
 		if (mc.level == null) {
 			return;
@@ -65,6 +82,38 @@ public final class TraderHighlightRenderer {
 
 		renderBoxes(mc, drawPose, consumer, camera, tickDelta, trader, inTicks, outTicks);
 	}
+	//?}
+
+	//? if traderWireframe121 {
+	private static void renderWorld121(WorldRenderContext context) {
+		Minecraft mc = Minecraft.getInstance();
+		if (mc.level == null) {
+			return;
+		}
+		KeybindCallbacks kb = KeybindCallbacks.getInstance();
+		Entity trader = kb.getTraderHighlightEntity(mc);
+		int inTicks = kb.getInputContainerHighlightTicks();
+		int outTicks = kb.getOutputContainerHighlightTicks();
+		if (trader == null && inTicks <= 0 && outTicks <= 0) {
+			return;
+		}
+
+		var vertexConsumers = context.consumers();
+		PoseStack drawPose = new PoseStack();
+		Vec3 camera = mc.gameRenderer.getMainCamera().position();
+		float tickDelta = mc.getDeltaTracker().getGameTimeDeltaPartialTick(true);
+
+		final VertexConsumer consumer;
+		//? if traderWireframe12110 {
+		consumer = vertexConsumers.getBuffer(RenderType.lines());
+		//?}
+		//? if traderWireframe12111 {
+		consumer = vertexConsumers.getBuffer(RenderTypes.lines());
+		//?}
+
+		renderBoxes(mc, drawPose, consumer, camera, tickDelta, trader, inTicks, outTicks);
+	}
+	//?}
 
 	private static void renderBoxes(Minecraft mc, PoseStack drawPose, VertexConsumer consumer, Vec3 camera,
 			float tickDelta, Entity trader, int inTicks, int outTicks) {
@@ -100,8 +149,13 @@ public final class TraderHighlightRenderer {
 	}
 
 	private static void renderShape(PoseStack drawPose, VertexConsumer consumer, AABB cameraRelative, int color) {
+		//? if traderWireframe12110 {
+		SHAPE_RENDERER.renderShape(drawPose, consumer, Shapes.create(cameraRelative), 0.0D, 0.0D, 0.0D, color);
+		//?}
+		//? if traderWireframeMc26 || traderWireframe12111 {
 		SHAPE_RENDERER.renderShape(drawPose, consumer, Shapes.create(cameraRelative), 0.0D, 0.0D, 0.0D, color,
 				LINE_WIDTH);
+		//?}
 	}
 	//?}
 }
diff --git a/versions/1.21.10-fabric/gradle.properties b/versions/1.21.10-fabric/gradle.properties
index 747077f..aa0cd52 100644
--- a/versions/1.21.10-fabric/gradle.properties
+++ b/versions/1.21.10-fabric/gradle.properties
@@ -1,7 +1,7 @@
 modstitch.platform=fabric-loom-remap
 deps.minecraft=1.21.10
 
-fabric_loader_version=0.19.2
+fabric_loader_version=0.18.3
 fabric_api_version=0.138.4+1.21.10
 malilib_version=0.26.8
 mod_menu_version=16.0.1
diff --git a/versions/1.21.11-fabric/gradle.properties b/versions/1.21.11-fabric/gradle.properties
index 613f2f5..00a9923 100644
--- a/versions/1.21.11-fabric/gradle.properties
+++ b/versions/1.21.11-fabric/gradle.properties
@@ -2,7 +2,7 @@ modstitch.platform=fabric-loom-remap
 deps.minecraft=1.21.11
 
 fabric_loader_version=0.19.2
-fabric_api_version=0.136.0+1.21.11
-malilib_version=0.27.3
+fabric_api_version=0.141.3+1.21.11
+malilib_version=0.27.9
 mod_menu_version=17.0.0
 minecraft_version_min=1.21.11