As I read it, the Bears from the 'ABC' islands of Alaska are now regarded as being more closely related to Polar bears than any other Brown bears are. That's how I interpret this anyway.
I appreciate that these neat, Linnean labels are getting increasingly hard to apply, but doesn't this suggest that these animals should be split off as a full species, Ursus middendorfi?
But I would also expect the nearest Brown Bear populations in other areas close to current Polar Bear habitat, e.g. around Hudson Bay, might throw up similar genetic patterns- if they were tested. It all seems as clear as mud to me.