I can only duplicate this when I use Nerocons method. The links of dustfinger also prduce the bug, but using the login button as described just results in it telling me that I entered invalid stuff, which is correct.
However, I noticed another effect that might be classified as \"bug\": when editing a post that is the last one of a thread, but this thread isn\'t the last one that has been posted to in the same forum (i.e., it\'s not at the top of the list), then the newly edited thread goes to the top (for a while), but the main page still lists the other thread\'s title as the most recent one. Clicking on the link takes you to the newly edited one, however.
not an issue anymore due to new forum software. --neko