(Case 1107819) Shader Unsupported: 'Legacy Shaders/Diffuse' - Pass 'Meta' has no vertex shader

Here is the bug-report for one of these issues. I'm still trying to get a reproduce for the other one.
https://forum.unity.com/threads/performance-overview.563446/#post-3927733

Unity outputs the following warning in a Windows 64bit Standalone Player:

Code (CSharp):

1. WARNING: Shader Unsupported: 'Legacy Shaders/Diffuse' - Pass 'Meta' has no vertex shader

Reproduce

• Open user attached project
• Build & Run a Windows 64bit Standalone Player
• Open player log file "C:\Users\%UserName%\AppData\LocalLow\DefaultCompany\Wolf\output_log.txt"

Observe it contains a "Shader Unsupported" warning

Actual
"Shader Unsupported" warning

Expected
Unity built-in shaders should not contain any warnings and errors.

 

I'm also getting this from a few shaders I've got in my project, once I've upgraded from 2018.1.0f2 -> 2018.3.0b12

This one produces the same error "Pass 'Meta' has no vertex shader" in the log file, but it all seems to work fine.

Code (CSharp):

1. Shader "Custom/AtlasShaderBG" {
2.     Properties {
3.         _MainTex("Texture", 2D) = "white" {}
4.         _EmisColor("Emission Color", Color) = (1,1,1,1)
5.     }
6.  
7.     SubShader {
8.         Tags {
9.             "Queue" = "Transparent"
10.             "IgnoreProjector" = "True"
11.             "RenderType" = "Transparent"
12.             "PreviewType" = "Plane"
13.             "CanUseSpriteAtlas" = "True"
14.         }
15.  
16.         Cull Back
17.         Lighting Off
18.         ZWrite Off
19.  
20.         CGPROGRAM
21.         #pragma surface surf Lambert nofog alpha
22.  
23.         sampler2D _MainTex;
24.         float4 _EmisColor;
25.  
26.         struct Input {
27.             float2 uv_MainTex;
28.         };
29.  
30.         void surf(Input i, inout SurfaceOutput o) {
31.  
32.             fixed4 cMainTex = tex2D(_MainTex, i.uv_MainTex);
33.  
34.             // Set pixel
35.             o.Albedo = cMainTex.rgb;
36.             o.Alpha = cMainTex.a;
37.             o.Emission = (cMainTex.rgb * _EmisColor * cMainTex.a);
38.  
39.         }
40.  
41.         ENDCG
42.     }
43.  
44.     FallBack "Diffuse"
45. }