uneven volume in MS4 string lines

In the attached excerpt, which has only a single Violin 2 (Solo) line, certain notes seem louder than they should be and some seem quieter. I've marked the quieter and louder notes with Q and L. This line started off in a MuseScore 3 score, where the volume was even for the whole line.

The loud notes are at the beginning of slurred phrases, but I have found a similar problem with a cello part with no slurs. Like with the violin part, some notes are louder or quieter than they should be because there are no score notations to suggest any kind of dynamic change.

Thanks,

Bob