Ability Cooldowns not activating on repeat use.

I'm able to activate abilities and it follows through, yet the cooldowns are not activated on every 2nd use. The ability appear seem to register server side, dealing no damage, however if there is a stamina cost attached to the ability it will still subtract stamina for its use.
Tried 4 servers, was able to replicate the bug each time.

Inconsistent ability activation and stamina costs.

Consistent ability usage.