On my 5th start on a recently new plane the pipe did the same thing. At the time, when I heard it wrinkle, I first thought part of the turbine went down the pipe as the igniter failed on the next start. I also thought maybe the last former may have been too tight and when it expanded, it could not move. Also, I noticed when I put it together, that the outer pipe was a lot thinner than what I normally get. Mine is welded on the exhaust end too. I do not plan on using it.