Not to steal your thread, but I am getting (brand new), just a bit of jerkiness at initial let-out (right when it normally engages). Even a pretty smooth, low rpm let-out. Is this a symptom of rivets? It may go away after a while, it's so new I'm not sure.
I don't think there are exact symptoms for the rivet failure, or that all have the same.
When mine went, there was no warning, it just went.
It seems that most are able to nurse the bike home though.