At present, the shaders do not work properly with Single Path Instanced Rendering, which is commonly used by XR headsets (HoloLens, MagicLeap One).

Please consider adding the following changes:

@MeshChain.cginc:

1. appdata_meshChain
{
UNITY_VERTEX_INPUT_INSTANCE_ID
...
}

2. struct meshChain_vertex
{
UNITY_VERTEX_INPUT_INSTANCE_ID
UNITY_VERTEX_OUTPUT_STEREO
...
}

3. meshChain_vertex vert(appdata_meshChain v)
{
meshChain_vertex o;
UNITY_INITIALIZE_OUTPUT(meshChain_vertex, o);
UNITY_SETUP_INSTANCE_ID(v);
UNITY_TRANSFER_INSTANCE_ID(v,o);
UNITY_INITIALIZE_VERTEX_OUTPUT_STEREO(o);
...
}

4. half4 frag(meshChain_vertex i) : COLOR
{
UNITY_SETUP_INSTANCE_ID(i);
...
}