Dumb question - do the 21's have a different gen seat/frame - less prone to this failure?Like I said earlier, it isn't structural (i.e., the seat isn't going to collapse on you or fail in an accident), but it is a problem in the frame, specifically the lift mechanism. There's no fix for it besides a new frame, and the problem is common knowledge among Nissan technicians and dealerships. If the new frame the dealer installed is doing the same thing, then the new frame has also failed. It isn't the first time I've heard of new frames failing quickly, one unlucky Rogue at our dealership went through two replacements in under a year. If it's been less than 12 months then a replacement will be covered under Nissan's parts warranty, which is separate from any warranty that may remain on the car. If so, the dealer shouldn't be giving you a hard time about replacing it again.