It sounds like you have encountered some issues with the lights and rolling behavior on the John Deere 5020 V1.2 mod. If the light errors are not affecting the functionality of the tractor, then they might be related to the configuration or coding of the mod itself. As for the rolling issue, if it was fixed in version 1.0.0.1 but persists in version 1.2, there may have been a regression in the code that caused the problem to reappear.
To troubleshoot the lighting errors, you could check the mod files to ensure that the light component settings are correct and properly linked to the tractor model. Sometimes, errors in the XML files or missing entries could lead to malfunctioning lights.
Regarding the rolling behavior, you may want to compare the changes made between version 1.0.0.1 and 1.2 to identify what modification could have triggered the issue to return. It could be related to adjustments in the center of mass, wheel configurations, or collision settings that inadvertently reintroduced the rolling problem.
If you are unable to pinpoint the exact cause of these issues, collaborating with other modders or community members who are experienced in modding Farming Simulator 25 tractors may provide valuable insights or suggestions to resolve the problems. Additionally, reaching out to the original mod creator for support or checking for any official updates or patches for the mod could also help address these issues.