Olroth's Resolve Unique Life Flask bug?

I bought the flask after trying the melting maelstorm flask (unique mana flask).
I could use the unique mana flask even at full mana, so i thought it worked the same way for Orloth's Resolve so i could get the guard before taking damage but it doesn't let me use it at full HP.

I don't know if that's an intended feature, but the bug I'm reporting is a little different, after looking through the passive tree I've stumbled upon the passive "Eternal Youth", which says "Life recovery from Flasks applies to Energy Shield instead", and after picking that node the game DOES allows me to use Olroth's resolve even at full HP/ES, however it gives me 0 guard, it also gives me 0 guard even if my ES is a bit damaged.

Same issue

Same, I'm guessing it has to do with the timing or ordering of conversion that the eternal youth node does as to why the flask doesn't see any life recovery at all

Yeah same man...but even if i had Eternal Youth, nothing happens but it uses the charge like a normal flask.
I also have Chaos Inoculation on my passive and I tried turning it off but I am not able to even use the charges on the Olroth Flask.
Super weird.

same here. I was testing it, and the guard only shows up when I'm actually healing damage directly to my health.

Same here! Wondering if worth the investment since it only heal to full ES with no guard after take eternal youth