I've been experiencing this issue myself over the last few days...

Interestingly, it felt the need to withdraw the IP address from eth1 temporarily also, before putting it back shortly after.

It then felt the need to withdraw my public IPv6 address, register a link local address, and then remove that as well.  ifconfig output at the bottom.

Note that this is IPv6 and VPN over wireless (eth1 is the wireless, eth0 is a 10/100 LAN port with nothing connected).

Hope it helps.

Jan  2 18:58:29 seven NetworkManager: <info>  Will deactivate the VPN connection 'PIPE', service 'org.freedesktop.NetworkManager.ppp_starter'.
Jan  2 18:58:29 seven NetworkManager: <info>  Clearing nscd hosts cache.
Jan  2 18:58:29 seven NetworkManager: <WARN>  nm_spawn_process(): nm_spawn_process('/usr/sbin/nscd -i hosts'): could not spawn process. (Failed to execute child process "/usr/sbin/nscd" (No such file or directory))
Jan  2 18:58:29 seven avahi-daemon[7192]: Withdrawing address record for 192.168.18.241 on eth1.
Jan  2 18:58:29 seven avahi-daemon[7192]: Leaving mDNS multicast group on interface eth1.IPv4 with address 192.168.18.241.
Jan  2 18:58:29 seven avahi-daemon[7192]: Interface eth1.IPv4 no longer relevant for mDNS.
Jan  2 18:58:29 seven avahi-daemon[7192]: Withdrawing address record for 2001:470:xxxx:17c:213:2ff:fecb:3300 on eth1.
Jan  2 18:58:29 seven avahi-daemon[7192]: Registering new address record for fe80::213:2ff:fecb:3300 on eth1.*.
Jan  2 18:58:29 seven avahi-daemon[7192]: Withdrawing address record for fe80::213:2ff:fecb:3300 on eth1.
Jan  2 18:58:29 seven avahi-daemon[7192]: Joining mDNS multicast group on interface eth1.IPv4 with address 192.168.18.241.
Jan  2 18:58:29 seven avahi-daemon[7192]: New relevant interface eth1.IPv4 for mDNS.
Jan  2 18:58:29 seven avahi-daemon[7192]: Registering new address record for 192.168.18.241 on eth1.IPv4.
Jan  2 18:58:30 seven NetworkManager: <info>  VPN service 'org.freedesktop.NetworkManager.ppp_starter' signaled state change 4 -> 5.
Jan  2 18:58:30 seven NetworkManager: <info>  VPN service 'org.freedesktop.NetworkManager.ppp_starter' signaled state change 5 -> 6.
Jan  2 18:58:30 seven pppd[19495]: Terminating on signal 15
Jan  2 18:58:30 seven pppd[19495]: Child process /usr/sbin/pptp aaa.bbb.ccc.ddd --nolaunchpppd (pid 19496) terminated with signal 15
Jan  2 18:58:30 seven pppd[19495]: Connect time 0.5 minutes.
Jan  2 18:58:30 seven pppd[19495]: Sent 3597 bytes, received 4269 bytes.
Jan  2 18:58:30 seven pppd[19495]: MPPE disabled
Jan  2 18:58:30 seven pptp[19500]: anon log[callmgr_main:pptp_callmgr.c:255]: Closing connection (shutdown)
Jan  2 18:58:30 seven pptp[19500]: anon log[ctrlp_rep:pptp_ctrl.c:251]: Sent control packet type is 12 'Call-Clear-Request'
Jan  2 18:58:30 seven pptp[19500]: anon log[call_callback:pptp_callmgr.c:78]: Closing connection (call state)
Jan  2 18:58:30 seven pppd[19495]: Modem hangup
Jan  2 18:58:30 seven pppd[19495]: Connection terminated.
Jan  2 18:58:30 seven pppd[19495]: Exit.

eth1      Link encap:Ethernet  HWaddr 00:13:02:CB:33:00
          inet addr:192.168.18.241  Bcast:192.168.18.255  Mask:255.255.255.0
          UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
          RX packets:5120 errors:9 dropped:780 overruns:0 frame:0
          TX packets:3689 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:1000
          RX bytes:4862155 (4.6 MB)  TX bytes:1267244 (1.2 MB)
          Interrupt:16 Base address:0x2000 Memory:d2000000-d2000fff