I had weird happenings like that and then the project would start
playing loud and seemed to be at a different speed and the parts seemed
to be out of time...and it wouldn't stop until I forced X2 down.
Happened three different times and then when I exported it would play weird
like that for a few seconds and then it would play the exported stereo .wav.
I re-ran the audio-configuration and it stopped doing that. Something, somehow
was changing the configuration file.
At work and don't remember all the lines but I did notice the first two were changed
after it ran. Best I remember they were "0" and had been changed to something, somehow.