i think i've read about this bug in bugs wiki and might have been fixed.. not sure, but it never happened to me before.. here's how it happened.
i restarted kmeleon.. naturally browser started with homepage in first tab, then due to laziness; i selected a page i've just visited from history instead of browsing to the page like i normally do.
the address in urlbar did not change to new page from history.. in that case was kmeleon forum and kept address from the homepage(ookosearch)
the problem is kinda sporadic, it doesn't happen every time.. but it happens.
tested with 1.5.1 and 1.5.2rc2.. same thing