In my first game, my 3 man group of sovereign, champion and a sand golum battled some mites. After the battle, when I moved my group on the next turn, a duplicate ghost of the green "selection" outline around the tile remained behind. It looked just the the green highlighted square around my group but was static and I could not get rid of it. I even tried moving back on top of it. It remained there turn after turn until I exited the game and reloaded. Then it was finally gone. Seems like some graphic buffer is not being cleared in some cases.

Edit: System is Win7 64bit, 8GB memory, Geforce 670 video card.