Mine has done it once, but it never triggered the CEL. Over the summer, outside temps between 95 and 100, I had been driving for about 7 hours and it started hard shifting when I hit stop and go traffic. The trans was also running at about 230 degrees, my engine was hovering between 210-220 because my water pump was on its way out. I stopped for a couple hours at a rest area, when i got going again, I never had the issue again.