Items take up multiple stacks at random

Certain mod-added items are doing the aforementioned annoying thing. So far I have noticed this happen to Banana (Faxpax) and Hamm's (ID).

I updated ID earlier today. I have not, however, updated Faxpax for some time.

The banana, upon consumption, produces a Banana Peel trap item. The Banana Peels produced by the separately-stacking bananas stacked normally.

The affected items aren't appearing in my achievements window.

 

Banana is not mine, unfortunately. It's Fax's, IIRC.

 

My mistake. Haven't updated Faxpax for some time either, though, so aside from changing a single word in parenthesis my report remains unchanged.

 

I noticed throwing knives doing the same thing earlier, so it's not restricted to mod content.

 

Also, only one of the stacks will be craftable, i.e. if I have a stack of 3 pear wines and a solitary pear wine I can only make one pear brandy.

I think this means items are receiving weird metadata at random?