Title is kinda vague, sorry, wasn't sure how to word it.

Occasionally, when you select a item in your inventory, and then close your inventory, when you try to click on a item in your hotbar it will instead act as if you clicked that item in your inventory. This usually unequips it, which is annoying.

The number keys do not produce this effect, only clicking the hotbar does. It doesn't happen 100% of the time, and i'm not certain if there's anything specific that needs to happen for this to occur.