"#% increased Life Regeneration Rate during Effect of any Life Flask" not working correctly

#% increased Life Regeneration rate during Effect of any Life Flask:

{Succour}
Normal Life Flask: not working
Blood of the Warrior: not working

{Ulaman Desecration (Belt)}
Normal Life Flask: working
Blood of the Warrior: not working

I tested each piecemeal while having missing life and observing the changes to the character screen. None of the life flasks used had instantaneous life regain.