In every one of my SIP sessions FreeSwitch appears to be inserting ….

Contact: sip:mod_sofia@XXX.XXX.XXX.XXX:5060

Is this normal? 

I only ask as it is causing some of my end points to RE-INVITE back to this after the initial   ( INVITE  <---- >    100 Trying   < --- > 200 OK )   call setup.

If this is not normal or by design I can provide more details on configuration and dialplan.

Thanks!

Regards,

-Adam