(ok 3.2.3) Order by desc sometimes not working

Hi,

When I click on the column header, the order by isn't changed from asc to desc. This only fails for the functional columns, the others work fine.

SELECT p . * , from_unixtime( last_online_time ) , from_unixtime( p.ctime )
FROM `xwi_players` p
INNER JOIN xwi_serials
USING ( sid )
WHERE valid <0
AND ~ flags &2
ORDER BY from_unixtime( last_online_time ) ASC
LIMIT 0 , 30