diff --git a/src/main/java/net/neoforged/neoforge/items/ItemHandlerCopySlot.java b/src/main/java/net/neoforged/neoforge/items/ItemHandlerCopySlot.java
index 0f7ad24653c..735c036df07 100644
--- a/src/main/java/net/neoforged/neoforge/items/ItemHandlerCopySlot.java
+++ b/src/main/java/net/neoforged/neoforge/items/ItemHandlerCopySlot.java
@@ -38,7 +38,7 @@ protected ItemStack getStackCopy() {
 
     @Override
     protected void setStackCopy(ItemStack stack) {
-        ((IItemHandlerModifiable) slotItemHandler.getItemHandler()).setStackInSlot(index, stack);
+        ((IItemHandlerModifiable) slotItemHandler.getItemHandler()).setStackInSlot(slotItemHandler.index, stack);
     }
 
     @Override