Description of problem:
This is a wired ethernet network. Is connected to an Apple airport with IPv6 tunneling turned on; the tunneling is provided by Comcast/Xfinity.

While the network seems to work okay (including ipv6.google.com), journald is filled up with this representative sample:
 
May 10 10:39:35 mithos.talinet.net dnsmasq[997]: reading /etc/resolv.conf
May 10 10:39:35 mithos.talinet.net dnsmasq[997]: using nameserver 2002:62f4:3669:0:21e:52ff:fef1:811a#53
May 10 10:39:35 mithos.talinet.net dnsmasq[997]: using nameserver 10.0.1.1#53
May 10 10:39:35 mithos.talinet.net NetworkManager[787]: nm_ip6_config_add_nameserver: assertion `IN6_ARE_ADDR_EQUAL (nameserver, &nameservers[i]) == FALSE' failed
May 10 10:40:31 mithos.talinet.net NetworkManager[787]: nm_ip6_config_add_nameserver: assertion `IN6_ARE_ADDR_EQUAL (nameserver, &nameservers[i]) == FALSE' failed
May 10 10:41:18 mithos.talinet.net NetworkManager[787]: nm_ip6_config_add_nameserver: assertion `IN6_ARE_ADDR_EQUAL (nameserver, &nameservers[i]) == FALSE' failed
May 10 10:41:18 mithos.talinet.net NetworkManager[787]: <info> Policy set 'System p5p1' (p5p1) as default for IPv4 routing and DNS.
May 10 10:41:18 mithos.talinet.net NetworkManager[787]: <info> Policy set 'System p5p1' (p5p1) as default for IPv6 routing and DNS.
May 10 10:41:18 mithos.talinet.net NetworkManager[787]: nm_ip6_config_add_nameserver: assertion `IN6_ARE_ADDR_EQUAL (nameserver, &nameservers[i]) == FALSE' failed
May 10 10:41:27 mithos.talinet.net dnsmasq[997]: reading /etc/resolv.conf
May 10 10:41:27 mithos.talinet.net dnsmasq[997]: using nameserver 2002:62f4:3669:0:21e:52ff:fef1:811a#53
May 10 10:41:27 mithos.talinet.net dnsmasq[997]: using nameserver 10.0.1.1#53
May 10 10:41:27 mithos.talinet.net NetworkManager[787]: nm_ip6_config_add_nameserver: assertion `IN6_ARE_ADDR_EQUAL (nameserver, &nameservers[i]) == FALSE' failed
May 10 10:43:31 mithos.talinet.net NetworkManager[787]: nm_ip6_config_add_nameserver: assertion `IN6_ARE_ADDR_EQUAL (nameserver, &nameservers[i]) == FALSE' failed
May 10 10:44:26 mithos.talinet.net NetworkManager[787]: nm_ip6_config_add_nameserver: assertion `IN6_ARE_ADDR_EQUAL (nameserver, &nameservers[i]) == FALSE' failed
May 10 10:44:26 mithos.talinet.net NetworkManager[787]: <info> Policy set 'System p5p1' (p5p1) as default for IPv4 routing and DNS.
May 10 10:44:26 mithos.talinet.net NetworkManager[787]: <info> Policy set 'System p5p1' (p5p1) as default for IPv6 routing and DNS.
May 10 10:44:26 mithos.talinet.net NetworkManager[787]: nm_ip6_config_add_nameserver: assertion `IN6_ARE_ADDR_EQUAL (nameserver, &nameservers[i]) == FALSE' failed
May 10 10:45:11 mithos.talinet.net dnsmasq[997]: reading /etc/resolv.conf
May 10 10:45:11 mithos.talinet.net dnsmasq[997]: using nameserver 2002:62f4:3669:0:21e:52ff:fef1:811a#53
May 10 10:45:11 mithos.talinet.net dnsmasq[997]: using nameserver 10.0.1.1#53
May 10 10:45:11 mithos.talinet.net NetworkManager[787]: nm_ip6_config_add_nameserver: assertion `IN6_ARE_ADDR_EQUAL (nameserver, &nameservers[i]) == FALSE' failed
May 10 10:45:17 mithos.talinet.net NetworkManager[787]: nm_ip6_config_add_nameserver: assertion `IN6_ARE_ADDR_EQUAL (nameserver, &nameservers[i]) == FALSE' failed
May 10 10:45:17 mithos.talinet.net NetworkManager[787]: <info> Policy set 'System p5p1' (p5p1) as default for IPv4 routing and DNS.
May 10 10:45:17 mithos.talinet.net NetworkManager[787]: <info> Policy set 'System p5p1' (p5p1) as default for IPv6 routing and DNS.
May 10 10:45:17 mithos.talinet.net NetworkManager[787]: nm_ip6_config_add_nameserver: assertion `IN6_ARE_ADDR_EQUAL (nameserver, &nameservers[i]) == FALSE' failed
May 10 10:46:01 mithos.talinet.net dnsmasq[997]: reading /etc/resolv.conf
May 10 10:46:01 mithos.talinet.net dnsmasq[997]: using nameserver 2002:62f4:3669:0:21e:52ff:fef1:811a#53
May 10 10:46:01 mithos.talinet.net dnsmasq[997]: using nameserver 10.0.1.1#53
May 10 10:46:01 mithos.talinet.net NetworkManager[787]: nm_ip6_config_add_nameserver: assertion `IN6_ARE_ADDR_EQUAL (nameserver, &nameservers[i]) == FALSE' failed
May 10 10:46:14 mithos.talinet.net NetworkManager[787]: nm_ip6_config_add_nameserver: assertion `IN6_ARE_ADDR_EQUAL (nameserver, &nameservers[i]) == FALSE' failed
May 10 10:46:14 mithos.talinet.net NetworkManager[787]: <info> Policy set 'System p5p1' (p5p1) as default for IPv4 routing and DNS.
May 10 10:46:14 mithos.talinet.net NetworkManager[787]: <info> Policy set 'System p5p1' (p5p1) as default for IPv6 routing and DNS.
May 10 10:46:14 mithos.talinet.net NetworkManager[787]: nm_ip6_config_add_nameserver: assertion `IN6_ARE_ADDR_EQUAL (nameserver, &nameservers[i]) == FALSE' failed

May 10 10:46:36 mithos.talinet.net dnsmasq[997]: reading /etc/resolv.conf
May 10 10:46:36 mithos.talinet.net dnsmasq[997]: using nameserver 2002:62f4:3669:0:21e:52ff:fef1:811a#53
May 10 10:46:36 mithos.talinet.net dnsmasq[997]: using nameserver 10.0.1.1#53
May 10 10:46:36 mithos.talinet.net NetworkManager[787]: nm_ip6_config_add_nameserver: assertion `IN6_ARE_ADDR_EQUAL (nameserver, &nameservers[i]) == FALSE' failed
May 10 10:46:36 mithos.talinet.net NetworkManager[787]: <info> Policy set 'System p5p1' (p5p1) as default for IPv4 routing and DNS.
May 10 10:46:36 mithos.talinet.net NetworkManager[787]: <info> Policy set 'System p5p1' (p5p1) as default for IPv6 routing and DNS.
May 10 10:46:36 mithos.talinet.net NetworkManager[787]: nm_ip6_config_add_nameserver: assertion `IN6_ARE_ADDR_EQUAL (nameserver, &nameservers[i]) == FALSE' failed


Version-Release number of selected component (if applicable):
Fedora 17, NetworkManager 0.9.4.0.7.git20120403.fc17

How reproducible:
Every reboot by default

Steps to Reproduce:
1. Have ethernet plugged in
2. Boot
3. Monitor journald
  
Actual results:
Log flooded

Expected results:
Assertion-failure free operation.

Additional info: