My AutoMeter PRO COMP line did this as well as my VDO Pro Cockpits, they arent completely sealed, meaning they arent waterproof, they will fog up when there is alot of moisture in the air, ****ty part is there isnt a way to clean the lenses.

As far as the difference, are your pressure gauges electric or mechanical?

the electric ones dont have the heat source that the mechanicals do.