It's highly likely they will have the same problem, since its the web address (URL) that the "last unread post" button (link) takes you to which is faulty - it contains a duplicate anchor (the bit of the web address after the hash # symbol). This started happening for me after the slight theme change to the mobile site, so I assume it is due to the rendering of the site in this mode.
Just checked using the mobile site on the desktop, and yes, the issue persists, so it's nothing to do with the end user, it's the server end that's at fault.