This is an archived snapshot of W3C's public bugzilla bug tracker, decommissioned in April 2019. Please see the home page for more details.
The query in group-010 is: for $x in //employee let $key := if ($x/@gender='male') then number('NaN') else 42 group by $key order by $key return <group key="{$key}" count="{count($x)}"/> I believe that two results should be accepted, one with the NaN group before the non-NaN group, and one with the non-NaN group before the NaN group. The order by by clause is a no-op here, because an implementation may chose either empty-least or empty-greatest for the default order for empty sequences. This choice determines whether the NaN group appears first or last.
I have removed the order by clause from the query and allowed the two results that I described.