After partisipating in the drinking contest and having to clean up the temple afterwards, it appears that the items you're supposed to pick up; Giant's Toe and Alto Wine, lock up ALL items of the same type for the duration of the entire game. Essentially making those items unedible/undrinkable, un-droppable as well as making them unable to be used in alchemy afterwards regardless of how many "regular" versions of those items you gather afterwards. The game doesn't clear out the quest versions of those items thus the stacks as whole are considered quest items.