Don't know if this is true or not as I am not a scientist nor a microwave expert but I got this little tidbit of info that I would pass on to you.
Valky
Hmmm, learn something new everyday!
Be sure to put the rice cooker at the edge of the turntable, NOT in the center. The microwaves cannot pass through the spider bracket that holds and turns the turntable tray. They just bounce off it, which causes the food above it to remain uncooked. Whether cooking cakes, or rice, or whatever -- items in the microwave should always be placed at the perimeter of the turntable so they travel through the bouncing microwaves as they revolve through the cooking space.
Valky