Entropic Wasting and Vitality don't mix.

[smithfield]

Vitality (from an Escort) does not trigger from Entropic Wasting.
I am presuming this is a bug.

[Effigy]

Not a bug. Regeneration effects don't trigger entropic backlash, and Vitality is a regen effect. Same reason you don't get backlash from a Regeneration infusion. Direct heals like Healing infusion and Healing Light from Celestial/Light will trigger backlash.

[smithfield]

Much obliged. There's always more to learn isn't there.

[Moasseman]

Not a bug. Regeneration effects don't trigger entropic backlash, and Vitality is a regen effect. Same reason you don't get backlash from a Regeneration infusion. Direct heals like Healing infusion and Healing Light from Celestial/Light will trigger backlash.

He's talking about "damage" from Entropic backlash triggering Vitality, not the other way around

Whether this is a bug or not I have no idea as Entropic Wasting isn't exactly damage but health loss but Vitality only specifies "when your life falls below 50%" and doesn't say anything about it being damage that drops it below 50%

[smithfield]

That is correct. I may have been too terse.

Just to be precise. With a CoE, that had gained Vitality from an Escort.
Run up enough Entropic Wasting to go below 50% HP.
Vitality does not trigger.