Occultist Void Beacon ascendancy bug (Reduced enemy life regen)

Hello

I just went up against the Atoll boss with a ghost on it that made it have insane life regen.

I noticed it regening more than i do dmg which i was wondering about since i have Void Beacon (100% reduced enemy life regen)..

I was standing close to it and using Wither, Blight, Essence Drain and Bane DoT but it still outregened my damage..
I also have Unholy Authority which makes hexex work vs hexproof enemies..

I then tested by buying frost bomb (75% reduced enemy life regen) and boom, then i could kill it...

Therefor I think the reduced life regen on Void Beacon is bugged.

Doesn't make sense for frost bomb with 75% reduced regen to work but my 100% reduced regen from ascendancy doesn't make a difference..