diff --git a/patches/net/minecraft/data/tags/TagsProvider.java.patch b/patches/net/minecraft/data/tags/TagsProvider.java.patch
index 7cf15ff1f62..902fb6012ce 100644
--- a/patches/net/minecraft/data/tags/TagsProvider.java.patch
+++ b/patches/net/minecraft/data/tags/TagsProvider.java.patch
@@ -62,7 +62,7 @@
                                      TagBuilder tagbuilder = p_323138_.getValue();
                                      List<TagEntry> list = tagbuilder.build();
 -                                    List<TagEntry> list1 = list.stream().filter(p_274771_ -> !p_274771_.verifyIfPresent(predicate, predicate1)).toList();
-+                                    List<TagEntry> list1 = java.util.stream.Stream.concat(list.stream(), tagbuilder.getRemoveEntries())
++                                    List<TagEntry> list1 = list.stream()
 +                                              .filter((p_274771_) -> !p_274771_.verifyIfPresent(predicate, predicate1))
 +                                              .filter(this::missing)
 +                                              .toList();
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
diff --git a/tests/src/generated/resources/data/minecraft/tags/block/test_tag.json b/tests/src/generated/resources/data/minecraft/tags/block/test_tag.json
index cfe909e22ba..ebd314ac3ec 100644
--- a/tests/src/generated/resources/data/minecraft/tags/block/test_tag.json
+++ b/tests/src/generated/resources/data/minecraft/tags/block/test_tag.json
@@ -8,7 +8,8 @@
     "minecraft:polished_andesite",
     "#minecraft:beehives",
     "#minecraft:banners",
-    "#minecraft:beds"
+    "#minecraft:beds",
+    "minecraft:dacite"
   ],
   "values": []
 }
\ No newline at end of file
diff --git a/tests/src/generated/resources/data/neotests_reloadable_reg_data_maps/data_maps/loot_table/effect_grant.json b/tests/src/generated/resources/data/neotests_reloadable_reg_data_maps/data_maps/loot_table/effect_grant.json
index c716281c920..ff7693fcb25 100644
--- a/tests/src/generated/resources/data/neotests_reloadable_reg_data_maps/data_maps/loot_table/effect_grant.json
+++ b/tests/src/generated/resources/data/neotests_reloadable_reg_data_maps/data_maps/loot_table/effect_grant.json
@@ -3,10 +3,6 @@
     "minecraft:blocks/copper_block": {
       "duration": 100,
       "id": "minecraft:nausea",
-      "neoforge:cures": [
-        "protected_by_totem",
-        "milk"
-      ],
       "show_icon": true
     }
   }
diff --git a/tests/src/main/java/net/neoforged/neoforge/debug/data/DataMapTests.java b/tests/src/main/java/net/neoforged/neoforge/debug/data/DataMapTests.java
index 8d0f52f2db6..1a6c79b64d4 100644
--- a/tests/src/main/java/net/neoforged/neoforge/debug/data/DataMapTests.java
+++ b/tests/src/main/java/net/neoforged/neoforge/debug/data/DataMapTests.java
@@ -317,8 +317,10 @@ static void reloadableRegDataMaps(final DynamicTest test, final RegistrationHelp
         reg.addProvider(event -> new DataMapProvider(event.getGenerator().getPackOutput(), event.getLookupProvider()) {
             @Override
             protected void gather() {
+                var effect = new MobEffectInstance(MobEffects.CONFUSION, 100);
+                effect.getCures().clear(); // Cures use a hash set (not linked) meaning that their serialization is not deterministic
                 builder(effectGrant)
-                        .add(Blocks.COPPER_BLOCK.getLootTable(), new MobEffectInstance(MobEffects.CONFUSION, 100), false);
+                        .add(Blocks.COPPER_BLOCK.getLootTable(), effect, false);
             }
         });
 
diff --git a/tests/src/main/java/net/neoforged/neoforge/oldtest/RemoveTagDatagenTest.java b/tests/src/main/java/net/neoforged/neoforge/oldtest/RemoveTagDatagenTest.java
index 7ac89d1be14..7ab7609506f 100644
--- a/tests/src/main/java/net/neoforged/neoforge/oldtest/RemoveTagDatagenTest.java
+++ b/tests/src/main/java/net/neoforged/neoforge/oldtest/RemoveTagDatagenTest.java
@@ -46,7 +46,9 @@ protected void addTags(HolderLookup.Provider provider) {
                         .remove(key(Blocks.ANVIL))
                         .remove(key(Blocks.BASALT), key(Blocks.POLISHED_ANDESITE))
                         .remove(BlockTags.BEEHIVES)
-                        .remove(BlockTags.BANNERS, BlockTags.BEDS);
+                        .remove(BlockTags.BANNERS, BlockTags.BEDS)
+                        // test removing optional IDs not present at run-time
+                        .remove(ResourceLocation.withDefaultNamespace("dacite"));
             }
         };