NAS-IP-Address, rlm_perl, and loopback

I'm having a couple of issues particularly pertaining to the NAS-IP-Address variable that is passed from the switch. When a client sends the auth-request, we find that the authorize function of our perl script is being executed multiple times for the same request. I would think that the authorize function would only be called once. This also leads into the second issue I'm having that when the perl script does run, it doesn't always pass the same data in the NAS-IP-Address variable. Half the time it is the correct information and half the time it is 127.0.0.1. Can anyone shed some light on why this is happening? Thanks.