condensation under metal roof

I have a home built in the 60's in central Florida. It can be humid here, and in the evening sometimes the dew point is such that the exterior walls of CMU houses sweat...and I'm sure the underside of the roof can as well as there is rapid cooling of the metal below the dew point. Two years ago, I had a metal roof installed. This used screw down panels on purlins over 2" foam board. The house has an unvented attic (mostly finish space against the rafters) with fiberglass bat between joists. What is interesting is that someone had cut a couple inches off the decking at the ridge- only on one side of the ridge. I climbed into the small section of actual attic space in the top of the house and noticed condensation forming around the decking on the side where the cut was made. I also noticed in the eve that overhangs on the same side where the cut was made that there was moisture working its way through the soffit as staining. Should I just seal all airflow? I thought about adding mechanical ventilation to the attic space but that wouldn't help with the soffit issue.