I can't find anywhere that shows why the ipv4 changes every time to a different node on the iPhone. This is on prem with no cell service in voice only mode. It selects nodes that have Call Manager Services Inactive. In the UCM when the App is registered it shows it is registered to the node in the CUCM Group.
CUCM Group - Sub 1 and Sub 2
Jabber Phone Services shows IP for Pub, Sub 1, Sub 2, Sub 3, TFTP 1.
Administration shows phone registered to Sub 1
Does this affect where the SIP or RTP traffic is communicating through?