SetPropertyBlock with renderer index not working during meta pass (GI)

I use instanced materials that need to contribute to global illumination by Englighten.

Basically, I need to pass the albedo color as a property of MaterialPropertyBlock.

This works fine when I use Renderer.SetPropertyBlock(MaterialPropertyBlock properties), but stops working when I use Renderer.SetPropertyBlock(MaterialPropertyBlock properties, int materialIndex).

The color is properly applied per-renderer in other shader passes (like ForwardBase etc.), but does not seem transmitted during the meta pass (Tags { "LightMode" = "Meta" }).

The issue does not seem related to that particular property. Any MPB property passed via the indexed overload does not seem to get picked up in the shader during the meta pass.

My meta pass is as follows:

Code (CSharp):

1. Pass
2. {
3.     Name "META"
4.     Tags { "LightMode" = "Meta" }
5.  
6.     Cull Off
7.  
8.     CGPROGRAM
9.  
10.     #include "UnityStandardMeta.cginc"
11.  
12.     #pragma vertex vert_meta
13.     #pragma vertex frag_meta_custom
14.  
15.     UNITY_INSTANCING_BUFFER_START(IB_MyCustomMeta)
16.         UNITY_DEFINE_INSTANCED_PROP(fixed4, _AlbedoColor)
17.     UNITY_INSTANCING_BUFFER_END(IB_MyCustomMeta)
18.  
19.     float4 frag_meta_custom(v2f_meta i) : SV_Target
20.     {
21.         FragmentCommonData data = UNITY_SETUP_BRDF_INPUT(i.uv);
22.  
23.         UnityMetaInput o;
24.         UNITY_INITIALIZE_OUTPUT(UnityMetaInput, o);
25.  
26.         fixed3 albedo = UNITY_ACCESS_INSTANCED_PROP(IB_MyCustomMeta, _AlbedoColor).rgb;
27.  
28.         #ifdef EDITOR_VISUALIZATION
29.             o.Albedo = albedo;
30.             o.VizUV = i.vizUV;
31.             o.LightCoord = i.lightCoord;
32.         #else
33.             o.Albedo = albedo;
34.         #endif
35.  
36.         o.SpecularColor = data.specColor;
37.         o.Emission = Emission(i.uv.xy);
38.  
39.         return UnityMetaFragment(o);
40.     }
41.     ENDCG
42. }
43.  

Is this a known limitation? Am I doing something wrong? I've been googling this to no avail.

 

I encoutered this problem too.

 

Reported the bug, case IN-8639.

 

Got a reply from support, Unity decided they will not fix this bug.