It does not work at all. It simply instantly sets all ferns to animation frame 3, which makes it invisible to see (which is what animation frame 3 is for.) I don't see how this has any difference at all to be honest, it has the same effect as labeling each amount of capacity as a different frame while breaking it completely.
Alright, I noticed a problem and moved the On collision with small fern and it's actions into a sub event, but it didnt change anything. I can still eat the ferns while they are invisible which is what i wasnt able to do before, but i dont want them to be able to be eaten while invisible. Although if I do manage to accidentily eat one, then it automatically skips to 1 capacity, therefore skipping 1 whole capacity number and animation frame. It doesn't even regenerate after fully eaten either.
My problem is only the damn timer, the timer starts, but stays at 0 and seems like it's resetting and none of these 'fixes' you have said make any sense to me or work in the slightest.