IMS registration resets after closing 'Phone Information V2' app (Android 16 March update)

[eliotcougar]

After my Pixel 9 PRO updated to the latest release (CP1A.260305.018), the IMS registration has become very unstable. Every time the phone leaves WiFi range, or if I manually toggle WiFi, or toggle the Airplane mode, the IMS registration status is lost and doesn't come back automatically, even if Shizuku keeps running in the background.
UPDATE: WiFi apparently has nothing to do with the loss of registration. I found a reliable way to reproduce the bug:
0. Start Shizuku, Start the TurboIMS.

1. Apply the configuration in TurboIMS.
2. Open the Android phone testing app (##4636##), then tap "Phone Information V2".
3. The IMS tab shows that IMS is registered, VoLTE is available. The HD voice calls work.
4. Close the phone testing app (or even if you just go back from the Phone Information V2 screen).
5. IMS registration is lost.

Interestingly, the IMS registration does not reset if you use the old Phone Information screen.

There may be other situations when Android resets the applied settings.

I have to manually reapply the settings in TurboIMS. Maybe there is a way to monitor the status of the IMS registration in the background and automatically re-apply the settings if it gets reset?

[Mystery00]

I'm sorry for the late response! I just followed the reproduction steps and did reproduce this situation. Re-clicking "Apply Configuration" can normally restore it. It may be that phone information v2 resets the carrier information when exiting (or writes back according to the configuration content before exiting), which overwrites the data written by TurboIMS in advance. It is recommended to avoid using phone information v2 or to re-use TurboIMS after using it.

[Mystery00]

Perhaps this is a bug in phone information v2, XD

[eliotcougar]

Perhaps this is a bug in phone information v2, XD

It is good to have this information somewhere as a note for users. Since opening Phone Information V2 is a common way to check for IMS registration status, letting users know about this bug should reduce confusion. Initially, I thought TurboIMS wasn't working.