This is a fairly old Panasonic microwave.
It does all the usual things that it is asked to.
The timer times.
The turntable rotates.
It seems to have developed a mind of its own.
Occasionally, after it is through heating and shuts off it does something
When the door is opened, the interior light comes on again and the turntable
During this time it is not trying to heat. The off button does not affect
this action. Close the door and the light goes out and the turntable stops.
After a bit it reverts back to normal and stays truly off as expected.
Is this phenomenon governed by the control electronics, which would probably
call for a replacement microwave or is it caused be the failure or
misadjustment of one or more of the mechanical switches that could be
remedied by a DIYer?