[basex-talk] Grouping and sorting

XQuery: let $type := <type> <item id="id1"><value>3</value></item> <item id="id2"><value>3</value></item> <item id="id3"><value>6</value></item> <item id="id4"><value>5</value></item> <item id="id5"><value>5</value></item> </type>

for $i in $type/item let $v := $i/value group by $v order by $v return $v

Result in BaseX: <value>3</value> <value>5</value> <value>5</value>

As I understand XQuery the result should be as follows: <value>3</value> <value>5</value> <value>6</value>

Where ist my mistake or is it a bug in BaseX?