core: DHCPv6 on multiple Interfaces takes wrong Interface/subnet

I use ipv6 with DHCPv6 Prefix delegation size 60. On 2 Interfaces I enter Track Interface. One with prefixID 0, the other with prefixID 1.

The DHCPv6 gives all devices from all Interfaces (VLAN) a IP from ONE subnet. In DHCPv6 leases you can also see, on Interface is always one Interfaces shown.

I think, its always the first Interface, where I set track interface.

when I look at /var/dhcpd/etc/dhcpdv6.conf

it´s shown as following:

subnet6 xx:xx:xx:8b00::/60 {
  range6 xx:xx:xx:8b00::xxx xx:xx:xxx:8b00::xxx;
  option dhcp6.name-servers xxx;
  prefix6 xx:xx:xx:8b08:: xx:xx:xx:8b0c::/63;
}
subnet6 xx:xx:xx:8b00::/60 {
  range6 2003:c7:746:8b01::1000 xx:xx:xxx:8b01::2000;
  option dhcp6.name-servers xx:xx:xx:8b01:xx:xx:xx:5672;
  prefix6 xx:xx:xx:8b08:: xx:xx:xx:8b0c::/63;
}

the --subnet6 xx:xx:xx:8b00::/60 – Entry is twice. I think, the second has to be subnet6 xx:xx:xx:8b01::/60 {

When I use only ONE track interface, it works fine.

OPNsense 20.1.6-amd64 FreeBSD 11.2-RELEASE-p19-HBSD OpenSSL 1.1.1g 21 Apr 2020 CPU Type | Intel® Celeron® N4100 CPU @ 1.10GHz (4 cores)

It could be a bug.