ken_b - 3:39 am on Mar 16, 2013 (gmt 0)
What version of FF are you using?
I wouldn't be surprised if your situation was a FF issue rather tham a Google issue.
I'm running 17.0.1 and the cookie recording is not at all reliable.
Sometimes the cookies show up in the current cookies list, sometimes they don't, sometimes they'll be listed multiple times, sometimes they don't get deleted, etc, etc, etc.