Some In-Roamers are seen using visited PLMN’s MME, SGW but they are still using home PGW even though static selection of SGW & PGW are configured in MME for all roaming MCC+MNC. That mean any visitor will Locally break out and use specific SGW & PGW for IMS and Internet APN. But few subscribers seen using their home PLMN PGW for IMS APN. What are the scenarios that can trigger the visitor to use their home PGW. Once purged from MME then subscriber start using visited network’s SGW and PGW, which is an expected behaviour. Also these few random subscribers have switched off and switched on their device and also hover between VoWiFi / Volte during their stay multiple times still the PGW used is their home PGW.
Please help to understand and decode this scenario.