No, dishes and other containers get heated by the hot food which had been heated by the microwave. You still will need to be smart and use an oven mitt or other pot holder when handling any container of heated food or liquid.

Don't know why you didn't notice it before, but in my experience, this has always been the case.

Dishes that get hot in the microwave, are not "microwave safe"...that means that there is some element in the dishes that absorbs microwave energy. Something like metal in the glaze or in the dish itself. Unless, or course, you are cookiung something like rice in them that takes at least 4 or 5 minutes and stays hot so long that it heats the bowl.
Test the dishes for microwave safety by putting a glass container of water and the dish in question in the microwave....heat for 30 seconds or so...or until the water boils and test the temprature of the dish. If it's hot it's absorbing microwave energy.
Linda C

Linda, I still think that there is a transfer of heat from the food or liquid. Good test process.

I made the mistake a couple years ago when I decided I wanted a few different inexpensive dishes to change out seasonally just for everyday. Found two patterns I liked at Pier 1 and only needed dinner plates. Only after getting them home and having one crack in the microwave, did I think to look on the bottom of the plate, duh! They were dishwasher safe, but nothing mentioned about microwaves. So, we kept some of the old corelle out, and when we need to heat for more than a few seconds, use the Corelle. In the past, I had some Irish stoneware that also cracked/crazed in a warm oven---so that might happen with other non-microwavable dishes also. (I have also done the water/dish test to see if something was micro safe).

I don't attempt to nuke with dishes in the microwave as they all seem to get hot -- even my Corning/Pyrex which I know is microwave safe.

I have a few plates, dishes and bowls that were designed specifically for the microwave which I use to reheat foods that aren't being heated in their storage containers. I have some clear glass bowls which don't seem to get hot that I use for nuking a lot of stuff -- soups, frozen fruit etc. None of this stuff is particularly attractive so I just think of it as another form of cookware used for the microwave.

I have some mugs of the new Fiesta line which is technically microwave safe and they get very hot so I have always assumed that all china/porcelein etc. will get hot and I haven't attempted to heat on any dish that I actually like and want to keep around for awhile :)

The OP had not changed her idshes, but she had used different microwave units. My old MW noticibly lost power as it got older, and I noted that my newer model got things a lot hotter a lot faster.

My observation was based on her statement that she had not changed dishware.

I have not done the test yet. I have been using the Corelle microwavable dishes for about 5 years. Could their properties change in that time?

My suggestion is that you are using your microwave differently....not only for thawing and melting cheese and chocolate but also for real cooking and heating large things.
Corelle is glass and should not absorb any microwave energy...it has to be coming from the food.
Linda C