I have, in my endless wisdom (

), found another bug. Since trolls are vulnerable to the death spell, I decided to try it out. Sure enough, the troll collapsed, and when I "tabbed" over the troll, it read as dead, and I got the standard 1400 XP. So anyway, the red circle remained under the troll. I then used Melf's Minute Meteors. Lo and behold, I killed it (for good this time) and got an additional 1400 XP. I have Baldurdash as well as the ToB patch. It works with spirit trolls also. Here's the screenshot.