PoE2 Kurgal's Gaze does not work with belt mod

Hello,

I have Kurgal's Gaze socketed to my helm.
I have "#% increased Life Regeneration Rate during effect of any Life Flask".
I use my Blood Of the Warrior which is a life flask according to tooltip.
My mana regeneration does not change and it should as I understand the effect of Kurgal's Gaze.

Thanks!