Media Texture Sample in Deferred Decal Material / Error X3004

[blurryroots]

I ran into an issue with a material working fine in previous versions.
Shader Compiler produces error “/Engine/Generated/Material.ush(1964,56-152): error x3004: undeclared identifier ´TextureExternalSample_Decal`”.

Steps to reproduce:

• Create new Material
• Change Material Domain to Deferred Decal
• Change Decal Blend Mode to Translucent
• Add Texture Sampler
• Set the Texture Reference to a Media Texture
• Change the Sampler Type to External

Any ideas on how to resolve this issue?

[blurryroots]

Checkout my blog post describing the workaround.
TL;DR:

• Change MipMapValueMode in TextureSampler to “MipLevel” (Absolute)
• Feed 0 as the default MipLevel