dockerized kea has reservations outside subnet

When authorizing a kea-dhcp6 machine with Kea 2.0.0 as backend:

stork-0-agent-kea6-1              | ERROR DHCP6_PARSER_FAIL failed to create or run parser for configuration element subnet6: specified reservation '3001:db8:1:cafe::1' is not within the IPv6 subnet '3001:db8:1::/64'
stork-0-agent-kea6-1              | 2021-10-06 13:35:13.617 ERROR [kea-dhcp6.dhcp6/81.139893512860800] DHCP6_CONFIG_LOAD_FAIL configuration error using file: /etc/kea/kea-dhcp6.conf, reason: specified reservation '3001:db8:1:cafe::1' is not within the IPv6 subnet '3001:db8:1::/64'
stork-0-agent-kea6-1              | 2021-10-06 13:35:13.617 ERROR [kea-dhcp6.dhcp6/81.139893512860800] DHCP6_INIT_FAIL failed to initialize Kea server: configuration error using file '/etc/kea/kea-dhcp6.conf': specified reservation '3001:db8:1:cafe::1' is not within the IPv6 subnet '3001:db8:1::/64'

Out-of-subnet reserved addresses are no longer supported since kea#1254 (closed).