I was trying to reproduce another bug but I found this one instead.

Dragging and dropping any items from an external container to a cupboard visually duplicates the item in the cupboard container. I say "visually" as the two icons are clearly the same item just appearing twice. When one is removed from the container, they both disappear, also it's twin is grayed out when dragging.

Steps to reproduce:
1. Put item on ground near (empty) cupboard
2. Drag item from ground to cupboard icon and drop
3. Observe duplicated item

This does not work if the item is dragged from any equipped container, it has to be from an external container, e.g. another cupboard, a fridge, etc. I noticed this with the tote bag initially and this seems to be the most reliable to reproduce, but others I tested also showed the same behavior, pasta, namely.

Edit: I made sure to test with only this mod and it's required mod installed.