Healing Hands - Cleric's Hammer when out of mana

Healing Hands (0 mana cost through skill’s tree) don’t cast/trigger while on negative mana through Cleric’s Hammer, although they can still be cast manually.
I also took Seraph Blade (makes it an attack) and Rahyeh’s Chariot (movement skill), not sure if it affects that at all.
Didn’t test it with Hand of Aurelus (cast on Smite), cause don’t want to waste time leveling the skill back, maybe it doesn’t cast as well.

Pls fix, I want to put Sigils of Hope on autocast, and still be able to cast this 0-cost skill.

I can confirm that it also doesn’t cast using Hand of Aurelus while at negative mana and it being well under 0-cost. It’s rather frustrating.