oops there's another one

Author: MCTian-mi

src/main/java/gregtech/api/capability/impl/GTSimpleFluidHandlerItemStack.java

@@ -84,7 +84,8 @@ public FluidStack drain(int maxDrain, boolean doDrain) {
 
     private void removeTagWhenEmpty(boolean doDrain) {
         if (doDrain && this.getFluid() == null) {
-            this.container.setTagCompound(null);
+            var tagCompound = container.getTagCompound();
+            if (tagCompound != null) tagCompound.removeTag(FLUID_NBT_KEY);
         }
     }