ddns-tuning hook lib fails to unload during reconfigure command

Loading ddns-tuning library and running at least and submitting at least one client message (e.g. DISCOVER, REQUEST..) causes the libary to fail to unload entirely during reconfigure command:

2022-04-26 08:15:08.816 INFO  [kea-dhcp4.ddns-tuning-hooks/5581.140041746450560] DDNS_TUNING_UNLOAD DDNS Tuning hooks library has been unloaded
2022-04-26 08:15:08.816 DEBUG [kea-dhcp4.hooks/5581.140041746450560] HOOKS_UNLOAD_SUCCESS 'unload' function in hook library lib/kea/hooks/libdhcp_ddns_tuning.so returned success
2022-04-26 08:15:08.816 DEBUG [kea-dhcp4.callouts/5581.140041746450560] HOOKS_ALL_CALLOUTS_DEREGISTERED hook library at index 1 removed all callouts on hook ddns4_update
2022-04-26 08:15:08.816 DEBUG [kea-dhcp4.hooks/5581.140041746450560] HOOKS_CALLOUTS_REMOVED callouts removed from hook ddns4_update for library lib/kea/hooks/libdhcp_ddns_tuning.so
2022-04-26 08:15:08.816 ERROR [kea-dhcp4.dhcp4/5581.140041746450560] DHCP4_PARSER_COMMIT_FAIL parser failed to commit changes: some libraries are still opened
2022-04-26 08:15:08.816 FATAL [kea-dhcp4.dhcp4/5581.140041746450560] DHCP4_CONFIG_UNRECOVERABLE_ERROR DHCPv4 server new configuration failed with an error which cannot be recovered
2022-04-26 08:15:08.816 ERROR [kea-dhcp4.dhcp4/5581.140041746450560] DHCP4_CONFIG_LOAD_FAIL configuration error using file: /home/tmark/labspace_var/kea/etc/v4/1548.conf, reason: some libraries are still opened
2022-04-26 08:15:08.816 FATAL [kea-dhcp4.dhcp4/5581.140041746450560] DHCP4_DYNAMIC_RECONFIGURATION_FAIL dynamic server reconfiguration failed with file: /home/tmark/labspace_var/kea/etc/v4/1548.conf
2022-04-26 08:15:08.816 DEBUG [kea-dhcp4.commands/5581.140041746450560] COMMAND_SOCKET_WRITE Sent response of 160 bytes (0 bytes left to send) over command socket 32
2022-04-26 08:15:08.816 DEBUG [kea-dhcp4.commands/5581.140041746450560] COMMAND_SOCKET_CONNECTION_CLOSED Closed socket 32 for existing command connection
2022-04-26 08:15:14.573 DEBUG [kea-dhcp4.commands/5581.140041746450560] COMMAND_SOCKET_CONNECTION_OPENED Opened socket 21 for incoming command connection
2022-04-26 08:15:14.573 DEBUG [kea-dhcp4.commands/5581.140041746450560] COMMAND_SOCKET_READ Received 32 bytes over command socket 21