100% World Completion bug
had same thing to fix this you go to the ‘Order Of Whispers cave’ inside bloodtide coast and enter the instance this should give you the gift & star
If re-entering the Chantry of Secrets does not award you the Gift of Exploration, re-visit every map, including cities and WvW maps to make sure you have accepted each map’s reward chest. Failing to do this will also cause the ‘error’. Good luck.