Steps to reproduce:

1. Open attached project
2. Build 'TestScene' for iOS
3. Build the generated Xcode project to a device
4. Notice the WebCamTexture is correctly rendered to a RawImage texture
5. Rotate the device once to any other orientation
6. Notice that WebCamTexture fails to render on the RawImage after that, instead renders as a single color block

Note:
Reproduces on all graphics APIs.
Does not reproduce if you render the WebCamTexture on a 3D object (cube, plane, etc.).

Not reproducible with: 5.3.5f1