proxy login + redirection

On 'normal' loginRequest we get a '59923' (Redirect user to different post office) status code back together with new/correct IP + port in loginResponse, but on a 'proxy login' this redirection does not work - we will get back a failure '53505' (User not on post office).
Only workaround is to specify full qualified UPD (user.po.dom). - Is that by design?

I could swear, this wasn't that way in GW7 ...
(Env: 12.0.2)


Markus