I had the same problem with my 2010 Edge. It was frustrating, many trips back and forth to the dealer, since I'm still under warranty. They seemed baffled as well. After several attempts with recalibrating, turns out it was a bad cell in the battery. They replaced the battery and works like a champ! However, I did have to recalibrate by zone by following the instructions in the owners manual (driving in circles). Battery is an easy thing to check. Hope this helps.
Willmaster...