The 'Add 'Group' column automatically' option is designed to add the column when you manually switch the display into Grouped mode (and remove it when you manually turn grouping off). It's basically a shortcut so you can quickly group the list without having to go and add the column as well. It's not meant to override folder formats - if you want a folder format to add the Group column, simply edit the format and add the column to it.
Fair enough. However, I have to say that I was surprised to find specific Path Formats for col://Duplicate and coll://Find.
The Folder Formats: Detailed Guide says..
The same guide includes an image containing entries for col://Duplicate and coll://Find so maybe these coll::// entries have always been included in the default set of preferences and I have just never noticed.
