There was another topic for this issue, which was closed.
The issue is still happening (as of june 2025).
To add a bit more context. A temporary workaround is to delete save objects (cars, liveries, tunes, photos,…). This seems to delay the issue until you reach the previous number of objects. I’m saying “seems to” because I think it’s a little inconsistent.
Also another small addition: the change to the car seems to be persisted in the local savefile, as the livery is loaded if you get out of the car and get back in, but it’s not shown in the preview/thumbnail. eg:
