Fiddilesticks Bugged

I love playing Fiddle but their are too many bugs with his abilities primarily with Drain and Crow Storm. When I Drain I noticed if I become Immediately stunned right afterwards or right before I cast The Drain channeling bar counts down I see the Drain take place however, no Dmg is done or health is healed. This is very Confusing because if the drain was interrupted and the player does not realize the player will not act accordingly due to a system error not operator error. For Crow Storm I do not know if this is a bug or intended. Crow Storms Cooldown Does not become reset if Fiddle Sticks is interrupted during his crow Storm Cast (if this was the intention than the whole point of a Fiddlesticks is invalid).