I reproduced this twice on separate Sickly Diggles. When Targeting there was no problems but as soon as I hit both Diggles with a "Acid Ampoule Bolt" the health bar Bleeds across the screen as shown in images below. http://i966.photobucket.com/albums/ae146/Abominog_2010/Private/sick1.jpg http://i966.photobucket.com/albums/ae146/Abominog_2010/Private/sick2.jpg
I had the same issue on an Enraged Diggle when killing it with Nightmare Curse. http://i.imgur.com/WPNQe.png Seems the healthbar was somehow set to a negative and overflowed. Hitting it once more killed it.