Checking "Exclude from bill of materials" in the schematic or layout editor clears the LCSC number in the plugin

[MichaelRColton]

Describe the bug
When setting the "Exclude from bill of materials" box in the schematic or layout editor, the plug-in clears the LCSC number, this does not happen when toggling the BOM in the plugin itself.

The number can be restored with the "Find LCSC from mappings" command, but that shouldn't be necessary.

This is important to me because I am using the KiVar plugin to have multiple board variants. Because it sets the "exclude from bill of materials" box, a bunch of LCSC numbers get cleared, I then have to restore all the LCSC part numbers when I switch to another board variant.

I hope I'm just doing something wrong! Thanks for the amazing plugin and all the hard work!

To Reproduce

1. Have a component in the design, with "Exclude from bill of materials" unchecked.
2. In the plugin, assign an LCSC number.
3. In the schematic (followed by update layout from schematic) or layout editor, set the "Exclude from bill of materials" box for this part.
4. In the plugin, the LCSC number will now be gone.

Expected behavior
The LCSC number should remain, as it does when toggling BOM in the plugin.

KiCad Version

Application: KiCad PCB Editor x64 on x64

Version: 9.0.5, release build

Libraries:
wxWidgets 3.2.8
FreeType 2.13.3
HarfBuzz 10.2.0
FontConfig 2.15.0
libcurl/8.13.0-DEV Schannel zlib/1.3.1

Platform: Windows 11 (build 26100), 64-bit edition, 64 bit, Little endian, wxMSW
OpenGL: ATI Technologies Inc., AMD Radeon(TM) Graphics, 4.6.0 Compatibility Profile Context 24.12.1.241127

Build Info:
Date: Oct 2 2025 13:29:53
wxWidgets: 3.2.8 (wchar_t,wx containers)
Boost: 1.88.0
OCC: 7.9.1
Curl: 8.13.0-DEV
ngspice: 45.2
Compiler: Visual C++ 1944 without C++ ABI
KICAD_IPC_API=ON

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