KEA: config error using file <ipv6> not within the IPv6 subnet

[patient0]

Please ignore this thread : I'm temporarly dislexic, 31a2 is not 31e2.

Update to latest 24.08 DEV Snapshot and switched to KEA. KEA doesn't start showing the following errors:

Sep 28 11:45:23 	kea-dhcp6 	30518 	ERROR [kea-dhcp6.dhcp6.0x3dac2a812000] DHCP6_INIT_FAIL failed to initialize Kea server: configuration error using file '/usr/local/etc/kea/kea-dhcp6.conf': specified reservation '2a02:169:31a2:1969::f:52' is not within the IPv6 subnet '2a02:169:31e2:1969::/64'
Sep 28 11:45:23 	kea-dhcp6 	30518 	ERROR [kea-dhcp6.dhcp6.0x3dac2a812000] DHCP6_CONFIG_LOAD_FAIL configuration error using file: /usr/local/etc/kea/kea-dhcp6.conf, reason: specified reservation '2a02:169:31a2:1969::f:52' is not within the IPv6 subnet '2a02:169:31e2:1969::/64'
Sep 28 11:45:23 	kea-dhcp6 	30518 	ERROR [kea-dhcp6.dhcp6.0x3dac2a812000] DHCP6_PARSER_FAIL failed to create or run parser for configuration element subnet6: specified reservation '2a02:169:31a2:1969::f:52' is not within the IPv6 subnet '2a02:169:31e2:1969::/64' 

The IPv6 is - as far as I see it - within the subnet.

Am I missing something or hitting a bug?

addition: I got six IPv6 static mapping and the one throwing the error is the last one I created this morning. While still being on 24.08.a.20240624.0600.