We've just recently moved to using Amplify after updating to Unity 5.6 and have been recreating our car shaders using it.
We've ran into a specific issue on Android devices giving us an Artifact look on reflective materials. Most noticeable on our Metallic car paints. This also doesn't occur in the Unity editor, or on any iOS devices we've been able to test on.
On top of this, we are able to run the game on an old Motorola Razr droid with the metallic shader displaying correctly.
So it seems this is only occurring on higher end devices.
This is what the cars are suppose to look like in the garage
And this is what they look like in game on a huawei p9 ( Also tested on s5, s6 edge, htc one M8 with same results )
The effect is almost as if it's destroying smoothing groups of the mesh while also reflecting crazyness. Also note that the reflection of the alloys and bumpers have also either gone dark or gone matte.
Here's the shader used for it
Project is built using OpenGL2 only.