We’ve found a bug recently, where the playhead stops following the score, if new music is added to the end of score after the first playback.
If you add music to the end of score before the first playback, everything should be fine, the playhead follows the score to the end for the first time. But if you add (enough, usually more than four bars) more music and play it back again, the playhead will move out of the view, as soon as it reaches the newly added bars.
This pattern is hard to recognise because sometimes changing layout or page view/galley view resets the relevant states. I think it can also be triggered by inserting music in the middle of the score in which case the playhead leaves the view as soon as it reaches the inserted music.
I wonder if this is what you experience?