pfSense

After an IPv6 prefix and IP change on the WAN interface the KEA DHCP service crashes (after 1,5 to 2 hours) and cannot be restarted.
The IP and prefix change is not detected immediately and devices loose IPv6 connectivity. Additional bugs might be involved in the E2E IPv6 communication.
When the prefix change is detected after ca. 1,5 to 2 hours then the KEA DHCP service crashes.
A service restart on the GUI fails.

DHCP logs:
Dec 5 19:48:28 kea-dhcp6 82986 ERROR [kea-dhcp6.dhcp6.0x22b363c12000] DHCP6_PARSER_COMMIT_FAIL parser failed to commit changes: cannot lock socket lockfile, /tmp/kea6-ctrl-socket.lock, : Resource temporarily unavailable
Dec 5 19:48:28 kea-dhcp6 82986 ERROR [kea-dhcp6.dhcp6.0x22b363c12000] DHCP6_CONFIG_LOAD_FAIL configuration error using file: /usr/local/etc/kea/kea-dhcp6.conf, reason: cannot lock socket lockfile, /tmp/kea6-ctrl-socket.lock, : Resource temporarily unavailable
Dec 5 19:48:28 kea-dhcp6 82986 ERROR [kea-dhcp6.dhcp6.0x22b363c12000] DHCP6_INIT_FAIL failed to initialize Kea server: configuration error using file '/usr/local/etc/kea/kea-dhcp6.conf': cannot lock socket lockfile, /tmp/kea6-ctrl-socket.lock, : Resource temporarily unavailable

Scenario: IPv6 with dynamic IPv6 prefix advertised by upstream router via DCHPv6 to WAN Interface.
WAN IPv6 Configuration Type: DHCP6
DHCPv6 Prefix Delegation size: 61
Send IPv6 prefix hint: yes
Request only an IPv6 prefix: no

Clients are configured „managed“ (DHCP6).

Steps to reproduce:
Initiate a IPv6 prefix change on the upstream router.

Steps to work around:
Reboot pfSense.