[Serusers] t_relay to local domain?

Hi, Not sure if this is simply a dumb thing to do or the configuration is wrong... .8.14 SER is running mostly fine. 1) SER gets an invite to 123(a)domain.com 2) lookup() resolves this to 456(a)domain.com (serctl ul show 123 returns sip:456@domain.com) 3) t_relay is called and eventually get a 408 and the URI indicates 123(a)domain.com Logging has shown that the start of route logic is never called with 456(a)domain.com. It seems like the t_relay() is internally sitting on the location URI. Is this intentional, to stop loops from occurring? I realize that 'aliases' would better serve this but would like to understand what is occurring under the covers. Thanks in advance. Jim