Shaco Deceive
When you deceive (Shaco Q) while in autoattack range of an enemy quite often your stealth will be dropped automatically without you autoing anything, so you appear at the spot you deceived to completely visible. Especially easy to notice if you smartcast deceive.
Suppose it happens because stealth is dropped right at the millisecond an auto is started instead of there being any sort of delay.
Kills me quite a lot of the time.