The HighlightsAndShadows feature fails to work on Quest devices after upgrading from Unity version 6000.4.7.f1 to a higher version. In the Unity Editor, the issue manifests as purple rendering, while on Quest devices, the HighlightsAndShadows functionality completely fails. The regression is specifically tied to the Unity version upgrade path from 6000.4.7.f1, indicating a compatibility or breaking change introduced in later Unity versions.