Had the same thing happen once. Had AC running overnight and forgot to close the roof vents. When we woke up had same issue. Wiped it down and haven't had it occur again. Too much humidity inside the MH.
Good luck!
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2011 Sunseeker 3170ds "Ladybug"
2017 Jeep Grand Cherokee TOAD
Days camped 2015: 37; 2016: 66; 2017: 86 2018: 57 2019: 30