[Gameplay] Devour doesn't refund mana on first cast against monsters

Video shows exactly what is happening. Further examination of this bug reveals that Devour needs to be the first ability cast by Tahm for this bug to occur. To repeat the bug: Start a game, use Devour on a monster. This bug doesn't require anything else to work. I also included used runes in case they are the source of this bug: https://imgur.com/a/s7kWEHQ