Mordekaiser with hydra items

Recently played a few games with the new Mordekaiser. I tried him out with a titanic hydra rush. Now with both tiamat and titanic I have noticed the passive from both items and the active with titanic react strangely with his Q, as is sometimes it will proc on his Q hits and sometimes it will not. I have had it proc randomly with his 3 Q hits. Also if you use the active on titanic hydra after activating Q it will put the item on cooldown but the effect nor damage will go through. This does not happen every time though. It seems to be completely random. I would assume it should either work or not work. Not RNG. Its easily recreatable. Play Morde. Get either hydra item or tiamat. Start Q'ing things till they stop moving.