Anyone ever have a problem, where the user goes to page a. they then click to page b, where you set a cookie. Then, they click the back button, to page A, and then go back to page B. At this point, you'd expect page B to have the cookie you set, but it seems to be "unset" by the back button, and no longer appears.
This happens rarely and i expect that it has something to do with a browser setting. Yet I'm not quite sure. Any ideas?
People can configure their browsers to not accept cookies, and robots for the most part do not accept cookies.
Are you only setting a cookie on page B or do you try to set a cookie for every page past B. For instance do you see someone who goes A to B to C get two cookies issued to them (one on B and one on C)?
Try to look at your logs for more than two pages. If someone is refusing cookies then you will see a new cookie issued to an IP for every page requested.
Another scenario is that you have multiple people coming through the same IP and what you think is one person is really two.