Using half precision causes a lot of shader bugs, but you don’t see them until you run it on target mobile devices. As the Apple M1 is just a bigger A14 I assume it can support half precision, which will be quite handy for fixing half precision related bugs?
Currently we do not support half precision floats in shaders when targeting desktop platforms (including Mac), and use full precision floats instead.
While it is possible to manually edit “com.unity.render-pipelines.core\ShaderLibrary\Common.hlsl” to fix this for URP, this is will not be compatible with HDRP at the moment. We are aware of this issue though and are aiming to solve this soon.