No one said something cool can transfer heat to something hot. Cold absorbs heat.

I said as the food warms from the microwaves that heat transfers into the plate. I don't know about ceramics containing metal elements or not.

I do know that Corning Corelle is made from dufferent types of glass, as explained in the link. I have been using Corelle in microwave ovens for almost 40 years and it does not get hot the way a stoneware dish does.

I can only speak from my own experience. If I want to preheat a Corelle plate I have to put water on it as the water transfers heat into it.