A bug in the implemenation of your Analytics code on some pages, of G's code re that specific type of referral (they have been known to selectively mangle some referral URLs, including reversing bits of them!), a set of users with broken browsers frequenting the site in question, one moron with a broken browser following the link in question, a broken robot following the link in question...
IE, without a bit more detail I can see various irritating but benign reasons that this may be happening, only some of them to do with G.
Rgds
Damon