Musescore randomly changes note lengths and notes cut out

Hi,
Since updating to musecore 4 and using MuseSounds, I've noticed that at certain points musescore halves the note length of certain notes, and adds half a note length to others. I have attached some examples, where I've noticed this problem. I've also had problems with notes cutting out. These pieces are for my A-level music, and so these problems have caused me a lot of annoyance.

Examples of the Note Length issue:
- The Viola line in bar 1 of 'Theme of the Wicked', the 1st note is shortened.
- The Viola line from bars 32-37 of 'Theme of the Wicked', every other note is effectively dotted, and the notes in between are halved.

Examples of Notes Cutting Out:
- The Violin 1 line in bars 7-8 of 'Carpe Diem (World Cup 2026)'.

I've also had problems with solo instruments suddenly changing to a very quiet dynamic, and then reverting back to the original dynamic, although I can't find any examples at the moment.