dhcpcd lets ipv6 address expire and doesn't renew it

[SlOrbA]

Sep 01 15:08:04 pi dhcpcd[9532]: eth0: requesting DHCPv6 information
Sep 01 15:08:04 pi dhcpcd[9532]: eth0: rebinding lease of 192.168.1.10
Sep 01 15:08:04 pi dhcpcd[9532]: eth0: leased 192.168.1.10 for 86400 seconds
Sep 01 15:08:04 pi dhcpcd[9532]: eth0: changing route to 192.168.1.0/24
Sep 01 15:08:04 pi dhcpcd[9532]: eth0: changing default route via 192.168.1.254
Sep 01 15:08:04 pi systemd[1]: Started dhcpcd on all interfaces.
Sep 01 15:18:04 pi dhcpcd[9567]: eth0: fe80::nnnn:nnnn:nnnn:nnnn: router expired
Sep 01 15:18:04 pi dhcpcd[9567]: eth0: expired address 2001:nnnn:nnnn:nnnn:nnnn:nnnn:nnn:nnnn/64
Sep 01 15:18:04 pi dhcpcd[9567]: eth0: deleting default route via fe80::nnnn:nnnn:nnnn:nnnn
Sep 01 15:18:04 pi dhcpcd[9567]: eth0: deleting route to 2001:nnnn:nnnn:nnnn::/64
Sep 01 15:46:02 pi dhcpcd[10289]: eth0: soliciting an IPv6 router
Sep 01 15:46:02 pi dhcpcd[10289]: eth0: leased 192.168.1.10 for 86400 seconds
Sep 01 15:46:02 pi dhcpcd[10289]: eth0: changing route to 192.168.1.0/24
Sep 01 15:46:02 pi dhcpcd[10289]: eth0: changing default route via 192.168.1.254
Sep 01 15:46:02 pi dhcpcd[10324]: eth0: Router Advertisement from fe80::nnnn:nnnn:nnnn:nnnn
Sep 01 15:46:02 pi dhcpcd[10324]: eth0: adding address 2001:nnnn:nnnn:nnnn:nnnn:nnnn:nnnn:nnnn64
Sep 01 15:46:02 pi dhcpcd[10324]: eth0: adding route to 2001:nnnn:nnnn:nnnn::/64
Sep 01 15:46:02 pi systemd[1]: Started dhcpcd on all interfaces.
Sep 01 15:46:02 pi dhcpcd[10324]: eth0: adding default route via fe80::nnnn:nnnn:nnnn:nnnn
Sep 01 15:46:02 pi dhcpcd[10324]: eth0: requesting DHCPv6 information
$ dpkg -s dhcpcd5 | grep ^Version
Version: 1:6.11.5-1+rpt5
$ cat /etc/dhcpcd.conf | grep -v ^\#
hostname
clientid
persistent
option rapid_commit
option domain_name_servers, domain_name, domain_search, host_name
option classless_static_routes
option ntp_servers
option interface_mtu
require dhcp_server_identifier
slaac private