Renekton's Ruthless Predator is currently bugged

At first I thought I was just going crazy and not paying close enough attention, but it's happening to other people as well. There are certain situations where the Ruthless Predator goes on cooldown and begins the animation without actually stunning or dealing damage. It happens most often when an enemy champion moves into a brush right after the animation begins. This spell is severely important for Renekton's lane trades and this bug can completely ruin an early game 1v1 and swing the lane. Hopefully you can look into it