To reproduce:

1. Place a Sorting Chest
2. Put some random item into a slot inside the Sorting Chest
3. Immediately pick it up again and put it back and pick it up etc.

Sometimes it looks like it's duping the item, but that's just the screen going out of sync. However, the item deletion does actually occur.

Nevermind, I'm dumb... didn't notice exception spam in log, bug only added recently and never released.