The seats in the Laramie are only leather trimmed. The main seating area, where your issues seem to be, are not leather. I had an 18 2500 Laramie, never had any issues with the seat material. I'd think your warranty would apply here.
Close, but not correct.
The seating area where it's perforated, and where OP is having his issues, is actually real leather.
The backs of the seats are vinyl and the edges of the seats are microfiber and vinyl.
Again seating area is real leather.