In a score with parts, changing time signature after inserting measures at a section break causes corruption/crash

Issue type

Crash or freeze

Description with steps to reproduce

1. Create a new score for any instrument.
2. Set the first measures to 6/8 and a 2/4 time signature a few measures later + create part
   The test file at this step:

TestC.zip

3. In the main score, select the first measure in 2/4 and insert several measures before it.
4. Immediately add a section break at the end of the inserted measures.
5. At the start of the new section, change the time signature back to 6/8.
6. Open the part:

Actual result

The part displays the inserted 6/8 time signature, but the following 2/4 time signature is missing, unlike in the full score.
After saving, closing, and reopening the file, score corruption occurs and crashes are easy to trigger.

Supporting files, videos and screenshots

In which versions of MuseScore Studio is this issue present?

Version 4.7.3. I haven't check yet if the issue is active in previous versions.
EDIT: same issue in version 4.5.2

Regression

I was unable to check

Operating system

Windows11

Additional context

Problem raised here on the forum : https://musescore.org/en/node/393841

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