MuseSounds playback lag

I was writing the beginning of an adagio cue for strings (starting with a three-note anacrusis for the violas alone), and I noticed that the first of the three notes was not being held as long as the other two on playback. It seems not to start as soon as it's supposed to, even if I use the trick of highlighting an element such as a bracket at the beginning of the score, and even if I create an extra measure of rests before the start of the piece. However, the problem usually goes away if I tell MuseScore to use the Muse Sounds "Cellos" sound instead of the "Violas" sound. (It also goes away if I use MS Basic.)

I'm including a file to see whether you can reproduce the problem. The desired sound is for the three eighth-notes (quavers) in the anacrusis to be played evenly, with about the same amount of time spent on each one.

p.s. This problem has been present in the last several versions of MuseScore 4, including but not limited to 4.4.