When I tried it I did not "work" on the project, so wasn't likely to discover any arcane formula for reproducing the problem. It sounds like it happens to you unpredictably. How often? Is there anything you can recall that might be a trigger or a predictive sign?

It happens infrequently while I'm working. Can't locate anything that would trigger it and there's no predictive sign. Just occasionally I'll select the first tempo ratio button and the tempo is not adjusted.

Finally determined the cause: I occasionally insert some MIDI clips from the browser into my projects. Discovered that the MIDI clips had been inadvertently stored in the Audio clip folder. Hence, whenever I inserted a MIDI clip, Sonar thought it was something to do with audio. I've moved the clips into the MIDI Clip folder and my clock no longer resets itself. Although I have few posts, I've been using Cakewalk products before there was even ProAudio. Guess you really can learn something new every day.