Dastardly Curse should discard a characters oldest card when the character is damaged. Misguided Heal applies 2 damage before healing 4, unless armor prevents that damage. Dastardly Curse was applied to one of my characters and I utilized Misguided Heal. The damage was applied since the character had no way to prevent it, but his last card (a Slow card) was not discarded.
Not limited to misguided heal, it won't discard for any damage from allies now. Weird.. Play text needs to change into: Attach to target. Each time target takes damage from an enemy card, they must discard their oldest card.