I am away visiting family, so I have not been able to look anything except major bugs. Sitting at an airport, so knocking out a bit while I have a chance.
So, the cookie SHOULD be changing every page load, with a new cookie set for the same number of days from the point of that page load. It sounds like that is not happening. Because this is something that would involve a significant change on the server (small, but large impact), I am hesitant to make any functional changes. Instead, for now, I changed the cookie timeout to 14 days. It will most likely not update until the current one expires.