[GAMEPLAY] Vladimir - Some AoE skills can damage Vladimir while in pool

When enemy uses AoE skills on Vladimir ( Q, W, Q, E, E, etc) within ~0.25 second after he pools, even though you see his pool goes into CDR and hear sound effect, he still takes damage and sometimes it kills him while in pool. It seems like there is some "casting time" on vladimir pools because even though he can still move around and dodge targeted skillshots or autoattacks by pooling, he cannot dodge AoE skills for the first 0.25 seconds. I notice this quite often because 80% of time I play league, I play Vladimir and quite several times I died while in pool when enemy laner has no DoT or ignite to kill me while in pool. Actually this bug was present during season 3 also, but it was fixed early season 4 through some bug patch. Yet, it was reintroduced when Riot enabled Vladimir to use active items and summoner spells while in pool, which made it not a buff but a nerf to a seasoned Vladimir player. Since this bug was previously fixed, I believe it wouldn't be much difficult to fix it again.