Text style Stave sharing labels reverts to default after save/reload #35124

Issue type

Engraving bug (incorrect score rendering)

Description with steps to reproduce

1. Add staff or system text
2. Set its style to Stave sharing labels
3. Save and reopen
   Result: Style reverts to default

Supporting files, videos and screenshots

Screen.Recording.2026-10-03.at.06.43.39.mov

In which versions of MuseScore Studio is this issue present?

Nightly main

Regression

No.

Operating system

macOS 26.6.2

Additional context

No response

Checklist

• This report follows the guidelines for reporting bugs and issues
• I have verified that this issue has not been logged before, by searching the issue tracker for similar issues
• I have attached all requested files and information to this report
• I have attempted to identify the root problem as concisely as possible, and have used minimal reproducible examples where possible