diff --git a/src/main/java/appeng/parts/misc/ItemHandlerAdapter.java b/src/main/java/appeng/parts/misc/ItemHandlerAdapter.java
index fbc9f7abf..23a698873 100644
--- a/src/main/java/appeng/parts/misc/ItemHandlerAdapter.java
+++ b/src/main/java/appeng/parts/misc/ItemHandlerAdapter.java
@@ -122,6 +122,15 @@ class ItemHandlerAdapter implements IMEInventory<IAEItemStack>, IBaseMonitor<IAE
             do {
                 extracted = this.itemHandler.extractItem(i, remainingCurrentSlot, simulate);
                 if (!extracted.isEmpty()) {
+                    // In order to guard against broken IItemHandler implementations, we'll
+                    // try to guess if the returned stack (especially in simulate mode) is
+                    // the same that was returned by getStackInSlot. This is obviously not a
+                    // precise science, but it would catch the previous Forge bug:
+                    // https://github.com/MinecraftForge/MinecraftForge/pull/6580
+                    if (extracted == stackInInventorySlot) {
+                        extracted = extracted.copy();
+                    }
+
                     if (extracted.getCount() > remainingCurrentSlot) {
                         // Something broke. It should never return more than we requested...
                         // We're going to silently eat the remainder
@@ -131,19 +140,28 @@ class ItemHandlerAdapter implements IMEInventory<IAEItemStack>, IBaseMonitor<IAE
                         extracted.setCount(remainingCurrentSlot);
                     }
 
+                    // Heuristic for simulation: looping in case of simulations is pointless, since
+                    // the
+                    // state of the underlying inventory does not change after a simulated
+                    // extraction
+                    // To still support inventories that report stacks that are larger than
+                    // maxStackSize,
+                    // we use this heuristic
+                    if (simulate && extracted.getCount() == extracted.getMaxStackSize()
+                            && remainingCurrentSlot > extracted.getMaxStackSize()) {
+                        extracted.setCount(remainingCurrentSlot);
+                    }
+
                     // We're just gonna use the first stack we get our hands on as the template for
                     // the rest.
-                    // In case some stupid itemhandler (aka forge) returns an internal state we have
-                    // to do a second
-                    // expensive copy again.
                     if (gathered.isEmpty()) {
-                        gathered = extracted.copy();
+                        gathered = extracted;
                     } else {
                         gathered.grow(extracted.getCount());
                     }
                     remainingCurrentSlot -= extracted.getCount();
                 }
-            } while (!extracted.isEmpty() && remainingCurrentSlot > 0);
+            } while (!simulate && !extracted.isEmpty() && remainingCurrentSlot > 0);
 
             remainingSize -= stackSizeCurrentSlot - remainingCurrentSlot;