Apparentely it starts with no reason, but actually it starts because of qtranslate wordpress plugin.
You don’t ave to uninstall it as it is a valid tool.
Just it needs a little adjustment in its code.
As stated here:http://www.qianqin.de/qtranslate/forum/viewtopic.php?p=5988#p6142
it is sufficient to remove just one char from the file utils.php at line 151
$date_parameters = '#%#'; $strftime_parameters = '%%';
$date_parameters = '#%#'; $strftime_parameters = '%';
Just remove one out of two percentage symbols.