When fighting the hydra, I notice that whenever his passive proc, he puts his own skills on cd. It doesn't matter the team, as long as a shield is presented and attacked, he will put his own skills on CD.  Because of this he never gets a chance to use his skill EVER again and will be completely locked out of his skills.

Video for proof: https://www.youtube.com/watch?v=zdFOua4GARQ