If I select Fire Bolt (I'm controlling the imp), it auto-targets a square way over on the other side of the map:
That area is a bit broken up, because there was a mass of dragons over there, so I deployed a stone golem (amongst other things).
My theory: the stone golem killed the dragon with a quake, which also pushed the dragon (and a bit of wall) off the right-hand edge of the screen, where they wrapped around to the left. The game placed the dragon where it was shifted to, ignoring the fact that it is now dead. The imp is auto-targetting where the dragon was when it died.
edit: If I hit it with a fire bolt, I get a "Kill" message and gain XP, but it stays there (its hitpoints still go down). If I hit it in melee, I do no damage (no message at all), but still take retaliatory fire/cold damage, with the little glowing direction indicator pointing away to the right, not at the dragon. Definitely some part of the game thinks it's over on the other side of the map.
