After wasting a whole day on the phone. I finally got an answer and passed on to Crossroads.
I have a 2012 Sunset ST32FR layout. I took delivery of it Two weeks ago. I pulled down the AC filter to notice it was held their buy Two Rubber Bands and flapping around and letting in unfiltered air. I added Two more Rubber Bands and hopefully that will solve the problem.
Now for the Bigger Problem When you look up after removing the filter on the right hand side their is light showing through in about 4 or 5 spots. This represents outside air being sucked in and in my case living in Florida I have hot air being sucked in. It took a whole day of phone calls to find out the reason for the holes. They were put their by Dometic in order to mount a heat strip which is not my case or probably not most of yours. These holes should have been plugged up by the AC installer at Crossroads if a heat strip is not used in the AC unit according to a Tech. at Dometic I spoke to today.
My advise is to look and see if you have this issue.