This may be a known issue that will be fixed in Dorico 4 etc, or I may also have done something very wrong; I’m not sure which. But I’m sure it has come up before.
I have part of a score in which the cellos are divided into two sections plus a solo player. At one point, the solo player rejoins the rest of their section for several bars over a system break, so I changed the divisi from Solo + 2 sections to just 2 sections. This is the result in the first system:
And in the second system—note that section 2 still has music in the first two bars, before both sections recombine in the third bar for unison double stops, but this music is not visible. (Nor does it become visible when I turn off condensing.)
In the first image, the now-unused solo staff is labelled 1 and the staff corresponding to the first divisi section is labelled 2, with the staff corresponding to the second divisi section not having a label; this is incorrect. In the second image, obviously, the second divisi section is missing entirely, despite having two bars of music. (The solo player also should have an automatic unison with the first divisi section, but I assume there is no way to make this happen at present.)
Is there a potential solution for this issue at the moment (and did I do something to cause it), or should I just retain the solo part over the system break?