local keysig disappeares if it were at the begining of system and is not anymore

[sammik]

Issue type

Engraving bug (incorrect score rendering)

Description with steps to reproduce

1. score with at least two instruments
2. add local key sig to one staff
3. add line break on that place
4. remove line break
5. see - keysig disappeared

Supporting files, videos and screenshots

local-keysig-disappeares.mp4

What is the latest version of MuseScore Studio where this issue is present?

master (4.6)

Regression

Yes, this used to work in a previous version of MuseScore 4.x

Operating system

Unbuntu 22.04

Additional context

Works in 4.5 nigtly
Doesnt work in master (4.6) nightly

possibly may be caused by #26792

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