Editing causes all notes following not to sound

I'll be editing already written music and at some point all the notes following that edit point stop sounding on playback (both hands of a piano piece don't sound, even though I'm only editing one hand). Unfortunately, I can't figure out exactly what type of edit is doing it if, indeed, it's a particular editing action. I'm attaching the diagnostic zip file.

The workaround may give some clues: that is to select the quieted notes and either 1) change
Properties->Playback->Notes->Velocity or 2) use the up arrow to transpose the notes up a half step and then Ctrl-Z (hitting the down arrow can change the accidentals).

Also, the quieted notes still sound when they're clicked, but that doesn't resolve the issue.

Windows 10 Version 2009, Arch.: x86_64, MuseScore version (64-bit): 4.0.2-230651553, revision: dbe7c6d