I had a new kitchen and appliances put in. Now when the winter is here I've noticed that cold air coming in from my over the range microwave which has a vent on the outside wall. All the kitchen cupboard next to it are cold, the dishes feels like they been in the refrigerator. This past Sunday I had ice all over the microwave (see pictures)
Is this normal? I'm losing lots of heat this way.

Thank you

Assuming you have a combination microwave/fan, which is the norm for microwaves mounted over a range or stove. The vent to the exterior should have a little door that automatically closes when the fan is not being used. These usually have a small weight or spring to keep them closed. The are usually very light weight because the fan must be able to blow them open.

Look up under the hood on the exterior and see if such device is in place and that it is closing properly.