Oven burned some food, my wife said it looked like it reached 500 degrees, so I ran a test.

I set the oven to 250, which heated to that point, then beeped to indicate it reached temp, but the top element continued red hot, and the display changed from Preheat to Heating. I shut it off when the portable thermometer indicated 300+.

Last May the local service company replaced the Control Module to fix another issue, and it has been working fine for the last 10 months till this new issue.

Any thoughts on what it might be and things to check before I spend the $245 to have the local guy look at it?

Thank you.