On last 2.05 version
In a numeric field, if user put the zéro value, the result is not save because the function do_numerical in the file application/helpers/qanda_helper.php do a ltrim in the line 3436.

to resolve this just replace the line 3436
$fValue = ltrim($fValue,"0");
by
if($fValue !='0'){
$fValue = ltrim($fValue,"0");
}