Board Thread:General Discussion/@comment-35585214-20180909210204/@comment-2113997-20180909210644

It's explained on the page of Porunga's Wishes.

Porunga's Wishes wrote:

Note: The Five-Star Dragon Ball is obtainable from the weekly "Hidden Potential All Open" event only on the Japanese version, due to the event having a different ID number on the Global version, which wasn't updated by mistake. Any Hidden Potential stage during the rest of the week will work just fine.