I've noticed the same thing with up/down votes: if a page has been open for too long, my new up/down votes go away when the page is reloaded. After reloading, t

I've noticed the same thing with up/down votes: if a page has been open for too long, my new up/down votes go away when the page is reloaded. After reloading, they stick again. (I've never noticed this with flags.)