I can't see anything wrong in the QQ extension that would cause permanent damage to a forum.
The dev-master version has a leftover var_dump(), but it has not been released so it shouldn't be a factor.
Seeing the "are you sure" page when logging out points to the CSRF token having expired or being invalid. It might be because the window was opened for too long, that the server restarted or that the domain currently used is not the one listed in config.php.
