Is this a bug or by design?

Poultice does not take mana if you fail to place it. A 40 mana hit when a skill fails is brutal on a defender, especially a low int, not high mana, defender. If this is by design, perhaps make it half mana cost like lost concentration on spells, because right now, defenders spend hours upon hours sleeping. I have spent 120 mana for three failed bandages in a row and I'm screwed for 8 hours. Please make the defender have more awake time and less continually sleeping.

Thanks.