I ran the command /give @s minecraft:mushroom_stew[minecraft:max_stack_size=16] 16 that gives me a full 16 stack of mushroom stew, but when eaten the entire stack slot  turned into a single bowl instead of behaving like potions(drink one from a stack and you are given 1 empty bottle and subtract 1 from the stack). I also checked other stews like rabbit stew or beetroot soup, they all behaved wrongly aswell