cold food hot bowl is a direct sign of not having good microwaveable dishes.
My in laws have this white corelle stuff that swears it's microwave safe on the bottom but it gets hot as fuck when you reheat food. i don't think it's just because it's thin either if you try to melt butter in it the dishes get very hot.
The glass bentgo containers i use for storing food seem to be completely invisible to the microwaves. You can get food bubbling hot and still grab the glass container to pull it out and it's completely cool.
cold food hot bowl is a direct sign of not having good microwaveable dishes.
I've noticed some dishes degrade over time as well. I have some coffee cups that were fine for years, but nowadays if I microwave one for a minute I might as well be grabbing a motorcycle tailpipe when I go to take it out.
interesting! probably water molecules collecting inside through micro cracks over the years, it's the h2o molecules in food that act as the microwave susceptors