CB: Adding basic IPv6 subnet results in 0 lifetimes

I've configured CB and sent the following command:

echo ' "subnets": [ { "id": 100, "subnet": "2001:db8:1::/48", "shared-network-name": "", "pools": [ { "pool": "2001:db8:1::/64" } ] } ], "server-tags": [ "all" ] ' |
kea-shell --host ::1 --port 8000 --service dhcp6 remote-subnet6-set

and Kea printed out this:

2019-08-05 14:43:49.228 INFO  [kea-dhcp6.dhcpsrv/89148] DHCPSRV_CFGMGR_NEW_SUBNET6 a new subnet has been added to configuration: 2001:db8:1::/48 with params  preferred-lifetime=0, valid-lifetime=0, rapid-commit is disabled

This isn't correct. The problem lies with the log message itself, the underlying subnet structure seems to be configured correctly. There's a pref=3600, valid=7200 global value, with no specific lifetimes specified on subnet level, so global values are used.

Perhaps we need to get rid of the lifetimes printed or alternatively print zeros as "0 (use global or shared-network values)".

Since this seems to be logging only issue, treating as low.