Did the glaze on my ceramic bowl melt in the microwave?

So I was cooking, and in order to create a small table in the microwave, I flipped a bowl that I've microwaved for years upside down so that I could use its bottom as a table. When I opened the microwave 3 minutes later, there was a small amount of strong, sweet, almost pleasant-smelling smoke and some sizzling that was not the food.

There seemed to be something like candlewax and on the microwave turntable, and the bowl has small distortions, tiny like fingerprints on a piece of tape.

Did the glaze on the bowl (which is REALLY old -- we're talking they were my grandma's) melt? I've microwaved it lots before, but maybe flipping it and not letting steam out did it. If so, is eating the food cooked in the microwave dangerous?