Fizz grayed out E bug

Recently I have been heavily playing in the jungle. As we all know, one of his minor strengths as a jungler is his ability to jump a wall for objective steals. The first time this bug occurred, I was approaching the dragon wall with full vision on dragon to make a play for a steal. Upon reaching the wall my E suddenly grays out and cannot be cast. All of my other abilities are fine and I am moving around freely. It sucked but I didn't think too much about it. Then it happened in another game the same day. This time with Baron. The setup is exactly the same. We have full vision of Baron as i approach the wall prepared to make my play for a steal when suddenly for absolutely no reason, my E grays out again and I cannot bounce the wall to make the play. Both times it comes back after about 15 seconds or so. It actually did happen a third time in the same day but this time during a team fight. We were around the bottom side river in a team fight that was tilting in our favor. Halfway through the fight as a few enemies are reaching critically low health, i go to make a clean up play. As i start charging forward, my E suddenly grays out and i cannot use it at all. Needless to say I was caught by CC because of it and died. My E came back immediately after. I don't know if this is some sort of player tampering or just really unfortunate luck with a bug but each time this bug occurred, it had impeccable timing to screw me over.