Platform, device version and operating system: PC/Steam
Screenshot or image:
What you were expecting to happen, and what actually happened:
The opponent had two troops with only three health remaining. I cast Lamia which Charmed the bottom troop (Hobgoblin) who killed the troop above it (I forget, one of the horse looking ones). This should have given Lamia 8 mana, but she did not get any mana back.
How often does this happen? When did it begin happening?
Once. Killing with Charm earlier in the same match did refill mana.
Steps to make it happen again
I dunno. This occured in an Arena game.