Progress bar in epic doesn't show actual progress for child user stories from a different project area

Hi Team,
In my project I have an epic, which exceptionally has children in a different project area. I noticed that this epic doesn't display correctly progress bar for story points and hours - it's still 0/0, although children change their progress.

Epic (project area 1)
---> Story (project area 2)
-------> Task (project area 2)
-------> Task (project area 2)
---> Story (project area 2)
-------> Task (project area 2)
-------> Task (project area 2)
-------> Task (project area 2)

It it because progress calculation doesn't work across project areas? Is there any way to fix it?
Thanks
Robert