The "fix" is to remove the windows, separate the panes, clean the glass, and reassemble with a proper seal between the panes. RV dual pane glass doesn't have inert gas inside - just dry air. In round numbers, it costs about $200-$250/window to do the job right, so the repair cost is a probably a deal breaker unless the dealer throws it in. It's expensive to do them all properly, and I would worry they are skimping on the job unless they are already overpriced on the coach to start with.
Some places don't bother to repair - they just replace the window (about $300-$400 in many cases).
A fogged window may look ok on a dry (low humidity) day when the air between the panes dries out, but it will come right back the next cool, damp morning or evening.
2004 American Tradition; 2014 Buick LaCRosse
Homebase in the Ocala Nat'l Forest near Ocala, FL