BIRT report dont show all links (Parent-child relationship)

Good day everyone,

Im trying to do a BIRT report that shows me a workitem child-parent relation:

CHILD (TASK)     PARENT(MILESTONE)
0023                        01234
0024                        01235

I created 3 data sets:

1- Live Work Item CNT (list of al workitems filtering by "Type = 'Task')
2- Common Snapshot - LINKS (List of all links filtered by Type=parentworkitem)
3- Join dataset (LiveWorkItemCNT.WI_ITEMID = LINKS.SOURCE_ITEMID)

The problem comes out when i do that JOIN because the result shows me some CHILDS with no PARENT, and if i check the task (in RTC IDE)  i can see it has a parent.

im trying to create snapshots from every plan but nothing happen.

i share some caps:

For task (tarea) 2549 preview doesnt show any results


RTC shows that task have a parent


Hope anyone can help me

Thx in advance