Dropping produce sacks creates an empty produce sack object with collisions
If you are forced to drop it where it can't be dropped, it implodes and disappears. If that happens when you were crafting it, you do not get crafting materials back.
Suggested solution: forced drop (overflowing inventory, multi-crafting, etc.) always drops as item, not object.
Bag specific solution: If it can't be dropped due to insufficient space, it drops as an item on next attempt.