It is pretty common knowledge on all RV forums that "Pleather" covered furniture is prone to flake off after several years of use. It sucks but that is what it does on all RVs, not just Montana. In some ways, it is just like tires and brakes. They wear out and have to be replaced.
I see you complained about this exact problem 2 years ago (
https://www.montanaowners.com/forums...03#post1192503). I assume the problem has only gotten worse since then. I suspect you can replace the furniture for a lot less than any attempt to sue the vendor (which has zero to none probability for success).