I just had this very same problem. Tried repeatedly to add a favorite point to a cache using both IE and Firefox. It would increment the number of awarded favorite points, but when I looked at who marked it as favorite, my ID was not there. Back on the page for the cache, the number had returned to its original value. I finally awarded a favorite to a DIFFERENT cache, and then removed that point. Went back to the original cache and it then allowed me to assign the favorite point - and it stayed. Something is very flaky there!