Hello,
this happens because of session id appended to URL by your forum:
phpBB/faq.php?sid=f3df4ddcdf6d1c9345f790ec9652870f
You should manually modify your generator/config.inc.php file:
FIND:
'xs_cleanurls'=>'',
REPLACE WITH:
'xs_cleanurls'=>'#[\\?&]sid=.+#',