Mordekaiser ult bug

I've noticed when I build Rageblade on Morde, sometimes when I ult, it immediatly goes on cooldown when I cast it, and does nothing. As a result, I miss out on a timed heal, thus resulting in death most of the time. This has happened many times since the 5.23 update.

No they did not have QSS. I checked.

It seems most common against cc champs like lux.

If this could be looked into that'd be great.

On another note, Morde's q goves3 stacks instead of 2 each hit. While the stacking bug is awsome and OP, it is unfair and should also be looked into. LOL 3 stacks from all 3 q's! Huehuehue