If you do a search-not sure which forums-you'll find previous threads on this issue from about 5 or 6 years ago. We had a 2007 Thor unit that did this. It was the same issue - an inferior product had been used. If I remember it correctly, Thor had sent the material to Flexsteel.It was happening to lots of people at about the 5 year mark. As time went on, our seats looked like they had a disease. It's not a wearing out with age issue as some have alluded to. You'd have to see the seats to understand. Our friends have a 2012 Tiffin that did
this last year...at about the 5 yr. mark. In their case, Tiffin sent them new material, but they had to have them upholstered on their dime.