Hard to answer without knowing where you display the coordinates values.
For instance, in item change, you can get coordinates before modification.

Since coordinates of an item are relative to its parent, it may be normal to have (0,0) if it is a child item, as part of the group.

You might try to combine mapFromScene and mapFromParent to control extacly the reference coordinates system : scene, group, item?


S.Cascio