Typical scenario (all time-related are set to auto - zone etc, VPN):
- An airplane mode was switched on
- Then phone was turned off
- In few hours it was turned back on (airplane mode still on) - the time drifted as kinda expected
- The phone was kept like that for some time 10+ minutes (so I see DSU trying time.grapheneos.org frequently with no success as expected)
- Airplane mode switched off, so I see DSU reaching out GOS NTP several times (dunno if it succeeded though, but attempts stop)
Unexpectedly, time remains wrong for about half an hour after last NTP connection.
Dunno, maybe it has synced with cellular, finally, and not with NTP srv.
Symptoms are similar to "Network time synchronization is not working" https://github.com/GrapheneOS/os-issue-tracker/issues/340