Originally Posted by threeten

. At least one of the mobile/desktop view links was inadvertently not marked as such, and thus search engines will actually occasionally randomly follow those "switch view" links (which exists for every single forum post!) and consider that another possible webpage. Unfortunately it's probably too late now to remove all the links Google has crawled in its history - the only real solution is likely to disable the "styleid" key altogether, rename it, and be more careful about any future "switch desktop" or "switch mobile" links in the future.