Observations 2 (project with single stereo track plus 3 label tracks, about 80 minutes long):
It doesn’t matter which track has focus.
I’ve had it happen with horizontal zoom at Normal and when expanded 1 click.
Sync Lock ON/OFF makes no difference, at least once in the failed state. Deleting seems to be the trigger and I’ve always had Sync Lock ON then.
Displaying Preferences->Tracks and exiting via X or OK, even if “Update display while Playing” is toggled OFF and back ON, does not correct the state. I didn’t exit in the middle of toggling, so I might not have done a valid test. I’ll try that next time.
[EDIT] See my next post (Jan 12). [/EDIT]
Starting Play by clicking anywhere on the Timeline does not fix it, and therefore may be used to test for the state without changing it. I haven’t tested playing a range via the timeline. Starting Play by clicking on the Timeline also seems to have a better chance of producing the problem than starting it via the spacebar.
The failed state can initially appear when Play is started via spacebar. Spacebar does not fix it when it initially appears, but will fix it if used to start it again.
I haven’t determined whether it can initially appear when Play is started via Transport Play button. I’ve only tried this a few times and it hasn’t happened yet.
In a project of this length (about 80 minutes), regions where it happens frequently and regions where it happens infrequently seem to alternate. I wasn’t noting the location of each occurrence, so can’t quantify this yet. Also the opportunities (i.e. where I delete audio) aren’t uniformly distributed, which will make it more challenging.
When automatic scroll is failed, starting Play via either the spacebar or the Transport Play button will fix it. The fix occurs upon start, not stop, so it doesn’t matter how or where (on or off screen) Play is stopped - Transport Stop, spacebar, or reaching end of Select Range - if it was started via Transport Play button or spacebar, it’s fixed.
Deleting some audio (a fraction of a second to a few seconds in my observations, but I haven’t determined whether size matters) seems to be the trigger but it happens only occasionally. If audio is deleted while in the failed state, proper operation may be restored. I’ve tried this only once, so can’t say whether it always works.
Applying a Nyquist (fade by dB) or Audacity (amplify) effect after deleting does not change the state.