I just tested it myself. It seems to happen if you get caught in exactly the same frame as when you place an item, which I didnt foresee happening. I'll get to work on a fix!
Only other possible bug I maybe found was, after beating the game and restarting/replaying the game, the managers' dialogue at the intro doesn't appear properly (when still holding backpack) unless it was some other variable or random glitch that made him not talk
