A weird quirk I noticed is... When processing items, that is... doing a process that doesn't result in xp (i.e. smelting at the forge, grounding up items in mortar pestel, chopping on chopping board), when watching the red/green/white progress line, for items that result in 1 product (i.e. 2 copper ore results in 1 copper ingot, 2 plum results in 1 diced fruit, 1 werewolf claws results in 1 bonemeal), then if you hit Enter while the bar is in red there is no consequences, since there's no xp gain anyway and none of it is lost, even if you're doing a group of items.
However, if you do the same thing with items that result in multiple products (i.e. 1 quartz results in 2 fine sand, 2 bone results in 3 bonemeal, etc.) then hitting enter while the bar is red will result in minimal product; 1 quartz results in 1 fine sand, 2 bone results in 1 bonemeal).
I imagine this is because the calculation is per item instead of a stack of items, so the result per-item cannot be reduced below 1.
As a sidenote suggestion to the author: If we're not getting xp for processing, just make it a simple 1-click processing thing. There's enough timesinks in the minigame as-is.
Edit: Actually I take that back. It's inconsistent across the board whether it gives you reduced returns or not.