BTW: I did that one time.
I had Two 9" X 12" pans on the same rack, with Thighs in them.
There wasn't enough free space around the pans, so the heat below the pans was 250°, which is what my setting was. But the heat above was under 200°, because the heat couldn't get through, and the sensor was below the blockage, causing the element to shut off at the 250° that was below the blockage.
I moved one of the Pans to another level, and all was fine.
Bear
What he said!
It happens with overloaded situations or pan setups that like to trap heat and screw with airflow :)