Hello,
just want to report the following bug I found while testing Fairphone 4 in a lot of possible all-day-scenarios, of course with latest firmware.
If you use a german standard router device, like AVM Fritz!Box 7490, 7590, 7590ax etc. for internet access and you have a Fairphone 4 with latest firmware version constantly connectet via WLAN to this router:
After “forced separation” - “Zwangstrennung” at night, the Fairphone 4 does not have an IPv6 address any more and is only connected over IPv4 protocol. It only gets a new IPv6 adress under one of the following preconditions:
1.) Phone is manually rebooted by user.
2.) WLAN connection is completely interrupted*, because user leaves WLAN-covered area
3.) WLAN connection is completely interrupted*, because user switches WLAN manually off and on
*completely interrupted: No handover in MESH-network. Must be completely disconnected!
Interestingly, the other test devices - Samsung S20 and J5 and MotoG5 - does not have this problem…!
Perhaps this could be solved in a future firmware update 
Best regards
Achim