While cleaning control panel, removed knobs, did not turn stems but a surface heating element came on high and putting knob back would not adjust heat. Unplugged and read manual. Put all knobs back, made sure in off, plugged back in. ER light came on the one that had heated up., set clock and ER light would not go off. Repeated same result. Unplugged and let set an hour, repeated and tried anther element which worked fine. A couple minutes later an alarm sounded and the ER light went out. Now all seems ok. Is it likely there is issue I should have service tech check or is this normal?