This is odd but I think I understand what is going on, let me explain.
First off, I completely redid every item, erased them all reset their names to their id number z### set the item class to non-gameplay items, then I began the item creating, starting with id #0-#9 I created 10 levels of swords etc, etc... now what is happening is when an enemy drops an item i am getting the item with the id number of the ORIGINAL item (id #2 in this case, which is a sword, but originaly was a heart) I have 4 items that have the item class hearts but that is not what I am getting. It seems that the item class is not what is bieng called when an enemy drops an item but rather an Id number probley a slight oversight, hopefully a quick fix. (this may also help when *eventally* an itemset editor is made)
Enemy item drops not respecting customizations
Oof. You're right, item drops use item IDs, but that's unavoidable - the only other possibility is using (class, level) pairs, but these may not exist or may not be unique.
You'll need to wait for an item drop editor (coming post-2.50) which will let you fully specify what items are dropped.