Comment 21 for bug 761558

I finally could verify/reproduce the issues you were seeing with connections initially never start DHCPv6 even if they are showing "Auto" for the method -- there is another part of network-manager which uses the assumption that a missing method (e.g. for a new device connection, which typically doesn't necessarily have an associated file on the filesystem) means "Ignore", which is obviously false at this point.

I also noted that there is such a check in nm-applet which would write "Ignore" and then include the assigned IPv6 addresses if the above is fixed, so now we have two separate tasks for network-manager and network-manager-applet. I'm working on both, and they should be fixed shortly.

As for your crash, please try to reproduce it with apport enabled. You should see a file in /var/crash about this crash; we'd need this opened as a separate bug in order to be able to debug what is causing it. This is just so we can track each issue separately and know what is fixed and what isn't.