I have no direct knowledge to add regarding this, but if it were me I would see if Unspecified shows up for all printers as a separator for the list you want and the (Paper) selection. I suspect that when you select Automatically Select that the printer takes the paper type as the source. (guessing that many printers allow you to specify which paper type is in a specific tray) I also noticed in your Screen shots that before unspecified it appears that there is some padding infront of the names and after there is no padding.