Yep, I had the entire seat replaced yesterday myself. Like morphius says, the seat feels nice and tight, but we will indeed see. This is the second time they've replaced it (the first time was in December and the problem returned after about three months).
If it comes back, they will have to deal with me again.
I'm at 65000kms, so I'm out of warranty now. They said 90 day warranty on the seat. Great, it's already cooling down now and the seat only pops in hot weather, and it's going to be a beyotch to get them to fix things next summer since it will be well after warranty expiration.
WHAT exactly is the issue with the seat? The fACT that some people have had the seat replaced and it still persists makes me wonder they have no idea what is wrong.
I think the fact that this crap has been going on for three or four years should tell you that they have no idea how to fix this.
Don't let them get away with telling you that there is only a 90 day warranty on the seat. If it acts up again, take it back and raise hell, I don't care if it's a year from now.