This is [Hero Cantare] CM Liddie!
We would like to notify a known issue after the maintenance on December 13th PST.
> An issue where the 'Tetra Concert Mission - Collect all 4 Idols' cannot be cleared for certain players.
● The mission should be finished when the players possessed all of the 4 Idols.
● The issue was fixed by real-time resource patch at 22:50, December 13th PST, so please restart the app.
We sincerely apologize for your inconvenience and thank you for your patience.
Hero Cantare Team