I'm currently working on baking the texture of a tower. I followed the steps highlighted in this other answer Blender 2.8 Bake multiple textures into one but at the moment of baking of the final object with the starting texture a strange thing happens. For the bricks texture the baking operation seems to work, but for the other 2 materials it seems not to grasp colors and their distribution. In one case the system understands only the noise texture of a portion of the material. For the second case it does not understand the material at all leaving me with a black result.
The two problematic materials are respectively:
black and white image texture use as "fac" between two different shaders, one a mixture of gray and white thanks to a color ramp (and a noise texture as Fac), the other a mixture between an image and white thanks to a color ramp (again with a noise texture as Fac).
A simple material with a color ramp between gray and white and a noise texture as Fac