Tahm Kench devouring with 2 stacks

I have noticed when fighting Tahm Kench that he is able to devour you when there are only two stacks of acquired taste on your champion. If he gets three stacks on you and then they decay to two stacks he can still devour you, also sometimes two is enough even if he never puts the third stack on you. The length of the stacks are ridiculous on their own, but this makes it very difficult to avoid being eaten when two stacks are all it takes.