Interesting feedback. Thank you for playing :)
We tested all game mechanics before submitting and was sure this one was well worked. Would be nice if you tell us on what time it happened and with which ingredients. It would help us find this bug :0
I noticed it mainly with toxic ingredients not applying the reduction and increase of toxicity.
The one i remembered clearly was adding an eye to add a bit of toxicity, but it adding 0. Maybe it happend due to me adding milk first and it going into the negative, but i'd assume you clamped it 0 to avoid it.
Might also be that is purely visual.
In regards to what time, i believe it was on one of the last day or two, well into the game.