Microwave problem

Smaller cabinets tend to show the moisture more than large ones.
Consider heating the food a bit less......unless you are actually cooking it.

I do most everything by doubling the time and putting it on half power.
That way there are fewer hot spots, it tends to "boil over" less and the vent fan runs longer compared to the heating time.

Our Apollo Half Time convection/microwave does the same thing when microwaving. It actually has an AUTO DRY button on it that runs the convection for a couple minutes to dry that moisture.