Solo and Mute in Channel definition malfunction

I am attempting to bring the documentation for the instruments.xml file up to date (V3.5). I have found a number of problems that may be of no importance. Each is being reported as a separate ticket.

I cannot find any examples of use of Solo or Mute elements in a Channel element and I cannot see any use for them. Testing showed that their behavior was odd but, to a certain extent, reproducible.

1 Close all scores
2 Set the instrument list 1 to MuteSolo.xml
3 Restart MuseScore and load MuteSolo.mscz
4 Play - when I play, the score is silent up the the Solo
5 Create a new score with the same instruments
6 Copy the first 7 bars from MuteSolo to the new score
7 Play - Usually normal up to Mute, then piccolo muted up to Not mute, then piccolo sounds like piano up to Not mute set program, then normal until Solo which is ignored.

Have I screwed it up?

I would propose to mark these "Deprecated" in the instruments documentation