I have had this happen too. Always damp outside and with the engine not fully warmed up. Doesn't have to be on boost, just some throttle and I get some fogging.
I figured it was just moisture or condensation in the ducting.
- '00 Dodge Viper GTS - Steel Grey - Yep...a domestic.
- '87 930 - Guards Red - Sold
- '82 911SC - Grand Prix White - Gone
- '78 928 - Silver - Long gone
- '04 Subaru WRX wagon - Daily grind-mobile