Occultist's Void Beacon does not prevent Maven's Regeneration

bug reference: 404,532,952

While fighting the Atoll boss with Maven, it would massively regenerate health even while I was within melee range (I have the Occultist's Void Beacon allocated which provides 'Nearby Enemies have 100% reduced Life Regeneration rate')

Potential causes/interactions:
I might have been out of range when the healing started (Flame Dashing to avoid the Ice Nova)
Atoll boss is a Totem (I believe this has caused some other bugged interactions in the past?)

If this is an intentional interaction, I would appreciate knowing what I'm missing :)