Imp mama, malganis, reborn bug

In a battlegrounds match, the opponent is Lich King with reborn on Imp Mama.
Imp mama dies and spawns mal’ganis, which then gives the reborn Imp Mama 8/3. But Mal’ganis then dies and it keeps it’s 3 HP instead of going down to 1 HP when the Mal’ganis aura is removed.

Not a bug. Effects that increase health increase both maximum and current health. When this effect is removed, only maximum health is reduced.