Eternal Life + Black Doubt + Zealot's Oath = No Energy Shield?

Somewhere in this combination of perks and items, Energy Shield loses all ability to regenerate.

the idea was for Eternal Life to basically keep life full at all times, to make all regen "excess" to make Zealot's Oath recover Energy shield very quickly.

then Black Doubt would double up mana with life regen to keep life full if ES ran out.

but it just doesn't work.
Black Doubt + Eternal Life works, Zealot's Oath just won't share its toys.

also Eternal Life + Blood Magic just straight up doesn't work even though there's no reason it shouldn't since converting mana cost to life costs works.

anyone know the specifics on this? for why it wouldn't work?