[Gameplay] Fiddlesticks' Drain showing cast bars when interrupted

Sometimes ingame when Fiddlesticks gets interrupted, usually when he gets hit by some form of CC just as he attempts to drain, the HUD will still show the cast bar of Drain in spite of the fact that he is no longer using the skill.

This can cause quite a few preventable deaths in the event a Fiddlesticks player stands still doing nothing, not wanting to break the drain that they still think they're casting because the UI implies that they are.

Recreation procedure:

1. Be casting Drain
2. Get CC'd

Sporadic; seems to happen more often if Drain is cast at about the same time as the CC.