This has happened to me on numerous occasions.
I work on a project with pro L2 on the master and everything is working great. I then minimize ableton and to go work on something else for a while. Then, when returning to my ableton project and pressing play on my tune, I am subjected to the most horrifically loud and distorted noise imaginable. Truly ear bursting. I mean this sincerely. It really is dangerously loud, to the point where I believe if I had been wearing headphones at the time it could have damaged my hearing.
The issue persists until a restart of Ableton is performed.
I turned down the volume and went through all my plugins, to eventually find that Pro L2 is in fact the culprit.
Has this happened to anyone else?