Bug in undo-ing changes made by a plugin in MS4.6 - reproducible with simplest plugin & score attached!

Issue type

UX/Interaction bug (incorrect behaviour)

Description with steps to reproduce

To reproduce issue:

1. Open MS4.6.3
2. Install and Enable test plugin https://musescore.org/sites/musescore.org/files/2025-12/testH.qml
3. Open score https://musescore.org/sites/musescore.org/files/2025-12/test.mscz
4. Run plugin "testH" under "Composing/arranging-tools" - The plugin should add chord symbol "A" above the first (and only) note
5. Edit/Undo last change (or alternatively Ctrl-Z)
6. The test.mscz score should return to its state before running the plugin, and it indeed removes the "A" chord symbol. HOWEVER, the score is still marked as "dirty" (i.e. has an asterisk next to it)

The plugin does all of its changes within startCmd/endCmd of course of course.
And note that there are other scores where undoing the plugin (per step 5) returns to a clean state (no asterisk)

Supporting files, videos and screenshots

https://musescore.org/sites/musescore.org/files/2025-12/testH.qml
https://musescore.org/sites/musescore.org/files/2025-12/test.mscz

In which versions of MuseScore Studio is this issue present?

4.6.3

Regression

I was unable to check

Operating system

Windows 10

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