ERC exclusions lost when closing PCB Editor

Description

Apologies if this already exists as an issue, I did search but didn't find anything.

If I have a project with a schematic with some ERC exclusions, sometimes when I close the PCB editor (and I've observed it happening when updating the PCB from the Schematic too, but haven't reproduced it) while the schematic is open, the ERC exclusions are deleted from the .kicad_pro file. The exclusions are written back to the .kicad_pro file when I close the whole app, but this leaves a crucial period in the middle where git commits (externally or using the KiCad git client) will commit the removal of the ERC exclusions, leaving the door open to cloning it without the exclusions.

I have minimised it to a project that exhibits the symptoms every time below.

Steps to reproduce

1. Download this project

   bug_report_project.zip

2. Open the folder in a git client that will allow you to run git diff on demand

3. Open the project, open the schematic editor, open the PCB editor

4. Close the PCB editor (this deletes the exclusions from .kicad_pro)

5. Run git diff and observe the output is

   

6. Close the schematic editor and the KiCad application entirely (this writes the exclusions back to .kicad_pro)

7. Run git diff and observe the output is

   bug_report_project.zip

   

KiCad Version

Application: KiCad x64 on x64

Version: 9.0.3, release build

Libraries:
	wxWidgets 3.2.8
	FreeType 2.13.3
	HarfBuzz 10.2.0
	FontConfig 2.15.0

Platform: Windows 11 (build 26100), 64-bit edition, 64 bit, Little endian, wxMSW

	wxWidgets: 3.2.8 (wchar_t,wx containers)
	Boost: 1.88.0
	OCC: 7.9.1
	Curl: 8.13.0-DEV
	ngspice: 44
	Compiler: Visual C++ 1942 without C++ ABI
	KICAD_IPC_API=ON

Locale: 
	Lang: en_GB
	Enc: UTF-8
	Num: 1,234.5
	Encoded кΩ丈: D0BACEA9E4B888 (sys), D0BACEA9E4B888 (utf8)