"Industrial Environments with Eevee" Course: Columns Turning Magenta when Mixing in Second Principled BSDF
The problem has already been described by cchapeline here and on "Blender Stackexchange" here (but without any fitting solution for my problem). Despite exactly following Kent's theluthier instruction, the columns nevertheless turn magenta as soon as the second "Prinicpled BSDF" is mixed in with a "Mix Shader" node:
After muting the "Mix Shader Node":
With just the "Principled BSDF" with the paint color beeing plugged into the "Material Output" node:
Everything fine in Cycles:
All tests run with Blender 2.92.0 and 2.93 Alpha.