Sketchy playback, time not synced

I encountered a problem with MuseScore 4.3.1 where the playback was sketchy, stretching out certain parts so the music was off as much as two measures. If sounds like a processing problem. How do I get the parts to align and playback properly? It first starts showing up in measure 13.

I had this same glitch in the previous version. I started this project there, then shut it down, updated the program, then started inputting the information note for note once again. (I learned the hard way that cutting from one file and pasting in the other imported the glitch into the new file.)

Ii was going to play this for a Memorial Day event where my file would be as a Music-Minus One for solo cornet.