I had the same problem and recall i also had this problem a few weeks ago, and forums suggested deleting some mods I had running, so tried it again , deleting Questhelper and Arkinventory as they were showing to be memory hogs, and the problem went away.

But for some reason this problem only occured when i tried to use my 70 priest ?? both times, when loaded alone , and with my 2nd a/c