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Just FYI if you want to build to all you can simply not check any of the renderers. By default a shader will build to all renderers if no options are supplied.

This seems to be related

enabling all or disabling all seems to be ignored when opening a shader in SF and they all have to be changed again before saving

Unity recommended use for these target renderers anyway is when using platform specific shader technology. I am not so is there any benefit to building to fewer renderers? Does it save build time? when does the shader get built?

Noticing this also. I'm building to lots of platforms and it's easier to not use #pragma only_renderers at all. So I have to remember to disable those four renderers every time I make a change to a shader in ShaderForge.

It also gives a very misleading error 

"Your shader might not render properly on your workstation - you need to have Direct3D 11 enabled when working in DX11 mode on Windows. Click the icon to enable Direct3D 11!"

ALL renderers are enabled by default if exclude_renderers and only_renderers are not being used, that warning should only show if other renderers are explicity checked and Direct3D11 is not checked.

Some nodes are even showing textures from different shaders entirely