Your last post said that this happens with both ovens and at about the same time so I also doubt it is a bad connection caused by connectors heating up.
The time of when the error would be different for each oven.
The tech sheet shows that the control panel is monitored for connection all the time. Since you only get an error when using the ovens I would replace the control board/timer.
This is a gamble but is the more likely of the two parts.