It’s a visual mistake but could be very confusing for new players:
In an attempt to distinguish between opening the “Ancient chests” and the ones on the board, the latter were renamed to “Legendary chest”. (or because it’s finally fixed for rarity names R,E,L).
BUT: the task is still saying “ancient chests (in the board game)”.
Strictly speaking this is not possible as there are no Ancient chests anymore in the board, only outside the board game.
Please fix this once and for all