instant leech from claw mastery not functioning

Instant leech from the claw mastery does not appear to function.

current character: https://pobb.in/cB0oofB0htPG

Dual wielding Hand of Wisdom and Action, which should give me 20% instant leech. With the claw mastery allocated I get no instant leech at all, just a slow steady recovery from regular leech over time.

with 20% instant leech from claw mastery:
https://streamable.com/rarrau

With the leech mastery I get extremely quick and less smooth recovery, as expected from instant leech.

with 10% instant leech from leech mastery:
https://streamable.com/3v3ey6

I'd like to bump this, its still an issue