Righteous Fire bugged while having 1 hp, but thousands of Energy shield

I am using a build where i am fully based on ES, therefore im using zealot's oath, and i reserve 1.822 of 1846 life.
because of Zealot's oath keystone i have no life regen, but i do have 1400 energy dshield regen.

For chaos defenses i rely on Coruscating Elixir unique flask. Upon using the elixer; all but 1 life gets removed (part of the unique properties on this flask).

So here something strange is happening with RF;
Righteous Fire stops working for some reason. even though there is 7000 ES and 1400 ES regen, RF just stops.
Because you dont have any life regen in this build, life stays at 1.
Righteous Fire is now unable to activate. it seems it can not be activated while life is on 1 even though there is plenty of energy shield protecting the life.

EDIT
thanx for the reply. It is indeed as you say. I overlooked the line on the gem that says the effect is removed at 1 hp

Case closed :)

Working as intended. RF turns off at one life regardless of energy shield.