Auto save freaked out

While I was working on a mix, Sonar (6.2.1) decided to save it, and again, and again, and again ... It only stopped after I set the option 'save after x changes' to 0. Today, I opened the same projekt again and restored the original auto save settings, and the problem is gone. I somehow suspect a plugin to have caused the problem. Has anybody seen this happen before?

Thanks!

Wilko