Interesting, my RV repair guy said that if you are in a humid hot area you should run your fan on "low", so it does NOT freeze up. He said if the Snowbirds would do just that one thing of putting the ac fan on low when they get to Florida....he'd probably go out of business! :W
After paying for that repair call because my ac 'was' freezing up and not running right AND listening to his advice I never use high fan any more and it has never froze up again. And no it is not warmer in the coach using the low fan.
Low fan, clean filter inside OFTEN, and check and clean coils regularly.
Also, Don't know where you are parked but I ran across many areas that mid day the utilities back off the power, i.e. brown outs. I'd check what's coming in during that part of the day when it starts acting up.