phpwsbb module shipped with pws162
 

The table schema of phpwsbb_topics contains the columns lastpost_author_id and lastpost_author. The last mentioned column helds the login name of the poster, published in the forum list.

1st - I want to suggest, never to show the true login name to the (also anonymous) public for security reasons. Instead, the display name is to prefer to show any identity.

2nd - the column lastpost_author is redundant. To publish an author, simply call the mod users API like Current_User::getDisplayName()
I want to suggest to drop the column, because the values are not reliable in case some names become changed. The lastpost_author_id stored is sufficient enough in any case to call the (always actual) display name.

What I've seen was:
Class Topic.php line#399
$this->lastpost_author = $user->getUsername();
should be
$this->lastpost_author = $user->getDisplayName();
but I'm not sure if that is all.

Hilmar