Hi,

The problem was inside TeXmacs and has been fixed in SVN revision 12854.
If you do not wish to wait for the new version,
it suffices to change line 320 of std-automatic.ts into

<assign|part-info|<macro|name|<style-with|src-compact|none|<label|<merge|part:|<arg|name>>><write|parts|<tuple|<arg|name>|chapter-nr|<value|chapter-nr>|section-nr|<value|section-nr>|subsection-nr|<value|subsection-nr>>>>>>

Best wishes, --Joris



On Thu, Jul 23, 2020 at 06:59:54AM +0200, TeXmacs wrote:
> There is probably some kind of strange error with the way you included your files.
> You may send them to me in private if you wish and I can take a look.
> You may also try to isolate the problem by cutting text out of your documents
> until they become minimal while still having the problem.
>
> The bad plus/minus error might be due to the fact that the section number
> of some of the included documents could not be determined.
>
>
> On Tue, Jul 21, 2020 at 03:09:33PM -0400, CTO wrote:
> > I???m doing a document with a master and some included files; Style is ???generic??? with some fat margins. Setup is TeXmacs 1.99.13 on Mac OS 10.15.5.
> >
> > Everything is fine for awhile, and then more-or-less randomly the included files start showing all section headings with a prepended ???<error | bad plus/minus>??? . The version as rendered in the master is fine, as is a pdf export, so this is mostly an editing annoyance/distraction. Still, I use TeXmacs because the clean look helps me concentrate on writing, so a distraction is unfortunate.
> >
> > Any solutions?
> >
> >     m
> >