It used to be Saturday, Sunday, Monday of every week and should 100% be bought back..
What we believe is they want to make the 10$ crown pack and crowns for legendary chest a permanent thing in shop given how well it's done, so they've resorted to the scummiest tactic of a gut punch to the f2p players making them to either pay or quit the game forever
Every thing in this game has been slowly shaping to make more and more players p2w..
Overpowering defense so only way to take 3D remains is p2w with 5 and mind you overpowered TTs, Vault used to be a quarterly deal now we have no signs or even mentions of it, adding things for crowns but removing any reliable f2p source of gathering crowns..