Rakta Dark Dagger Max overshields on Finisher kill not always working with Hildryn

[ScaraX0]

Rakta Dark Dagger is supposed to grant you maximum Overshields when killing an enemy with a finisher attack that is affected by a Radiation proc.

This effect does not trigger reliably on Hildryn.

The Shield Leech on normal attacks against enemies with a radiation proc seems to work all the time, but doing finishers only seems to work every 4th-5th time. I know that I am doing finishers because I have Covert Lethality equipped and instantly kill level 150 enemies, and I know the enemies have a radiation proc because I see the Rad-Proc-Icon and they have a purple glow from the Dagger - but without proccing the Overshield effect.

The effect seems to be even less reliable when Haven is active - but I am not 100% sure about that.