> Shift the section plane a smidge one way or the other
That worked .... with some tweaking. If I attempted to place the section line very close to center visually, it would still fail, so I placed it almost an inch away. It works, but that's too far. So, I edited the section line, projected the flange I'm looking at to get the center point, deleted the original section line and recreated a new one. I placed it at .25, then .125, .06, and finally .015 away from center and it works.