Why is this happening to my guide bars? See the blue arrows on the pic. These are 2-20" bars and 1-16" bar off my Stihl MS290. The chain is getting stuck at this lower point on the bar and obviously getting very hot. After this happens once, the drive links get stuck there and then the bar is shot. The saw seems to be oiling properly. What else could cause this? I'm VERY tired of buying new bars!