Game Mechanics: SK Discipline: Leechcurse not working

[Nightbear]

For whatever reason, the last ~month~ Leechcurse hasn't been working. I've been trying to figure out the cause of the change. Another SK in my guild has said his sometimes doesn't work, but mine has had 0% uptime.

Discipline cooldown goes down, when I connect with melee attacks, no lifetaps happen, and no resists (if it even would show a resist message).

I've tried:
Full hp and not full HP
Full buffs and empty buffs
Velious content and non-Velious content
Low level mobs, debuffed mobs

Honestly would rather have Defense cap fixed but anyone else been having a similar issue?