Seeing it myself...
Of course it is already set in $this->page_title_error();
See public function main() in qa-theme-base.php
-- -- --
Then you change by:
function page_title_error() {
// change h1 which is the username
if($this->template=='user' && !qa_clicked('doaccount'))
{
$this->content['title'] = "test";
}
// default call
qa_html_theme_base::page_title_error();
}