Items are being duplicated and replacing other items, which disappear. This seems to be connected with using leads on animals.

I haven't been able to determine exactly _which _ actions cause this to happen, but at least twice it has occurred when I was using a lead to deliver a wild sheep to a pen. A duplicate stack of leads minus one was created, and that replaced some other item/stack in inventory. For instance, the bug most recently replaced a full stack of Jack-o-lanterns with five leads. That's just annoying; when it did this to my enchanted diamond sword, I had to recreate the sword in Creative mode. This may or may not be connected with the crash-and-dupe bug, which is another issue.

This particular problem has made the game almost unplayable for me, as items from my inventory are in effect randomly disappearing.