I’m not the biggest fan of Referback, as many of you already know. However, IE6 is still the norm, and the problem doesn’t occur in that version. It is entirely possible that the work they have been doing on the links was not done with IE7 in mind, not to mention that they may not have had anything to test with.
That being said, I still don’t see any place for pipes or other unusual characters in an URL. The sensible thing would be to ask Referback to remove that type of coding immediately, rather than harp on about whether or not this was intentional. Especially as it won’t be long before IE7 becomes the norm.
In the meantime, do as I have recommended many times in the past – either use their standard URLs without the double pipes – or remove them altogether until they fix this issue.