It should not work without unwrapping. If you are using a GLB format on import, then auto-unwrap will not work in the Editor - it is a known issue and being looked into. If I remember correctly, the engine, however, can still read UV1 channel at runtime and the lightmap will work when you start the app. If you use the previous import method (FBX/JSON), then the unwrapping should work and if it doesn’t, I would recommend creating an issue in the engine repo, so the team can look into it. A sample scene would help them with debugging: