A lot of our projects and products rely on our custom GPU renderer based on Graphics.DrawMeshInstanced calls to render models efficiently. Now suddenly after +8 years of working with this API, in Unity 2021.3.9 we receive this error: However the models are still being rendered properly but this error spams the console and makes the projects unusable. This also leads to a state where even none of Unity's own standard shaders working and receiving the same error! Since our solution was based on DrawMeshInstanced and we chose this to avoid needing to touch any shader codes whether it's a custom shader or Unity's and was working on all shaders by default, but it broke the entire ideology and affected our development heavily. So guides and hints on this from Unity graphics staff is strongly needed here since I guess it affected a lot of users.