When "Bake" is selected all is fine until preheat reaches 200F. At that point the fan that indicates convection baking starts and will not stop even after "Off" is selected on control panel. I tripped the breaker applicable to the unit and allowed it to remain off overnight. In the morning, after power was restored, no convection fan was running. When preheat for "Bake" topped 200F the convection fan began to run again. The control display still read "Bake." Twice again the convection stopped after oven cooled but restarted when preheat exceeded 200F even though "Bake" was selected. Any ideas are appreciated.