Hello @Sasa,
Any chance you can send us your project please ? Or at least a light version that reproduce the issue.
See 3) Provide Private Content
Regarding the “Upgrade All” process when opening an MSFS2020 project in MSFS2024:
It adds XMLs for textures (in modellib and simobjects) and update the PackageDefinition xml file by removing the MarketplaceData tag.
Additionally, it introduces a version type number (1 for ModelLib and SimObject, 0 for other AssetGroup types).
Regards,
Boris