So if you have a colour setup, which relies on displacement (that the SSS will also have) I notice that the SSS ignores the height based colours and only does the base colours.
First preview is PT, and second normal preview.
I do have non-UV images checked, though it made no difference.
I think this is a bug because if we're using custom shapes, and colour uses constraints that are also suppose to be in the volumes, it doesn't work.