Gameplay Bug - Rengar's Bola String

Rengar's 3rd ability, his Bola Strike, will sometimes bug when you cast it to reach max ferocity stacks causing the empowered Bola Strike to go on cool down. I have experienced this bug 3 times in the last 2 weeks while playing Rengar ranked. It occurs to me when I reach top river scuttler and I notice it when I go to use empowered Bola to snare it. It can be a game changing bug for Rengar if it occurs when he ganks a lane and he tries to use an empowered Bola on his opponent.