no boss spawn on Mao Kun map

i cleared the whole map, opend 7 booty chests, reenter to map and nothing happen. run the whole map like 4 times so far. on the atlas screen bonus is not checked.

is it a bug, or i should do sth special to spawn the last booty chest and final boss fight?

There are still ghosts that haven't been procced yet, somewhere then. IIRC you have to open 8 booty chests. The last chest causes a big ring of ghosts and fairgraves to spawn, not just fairgraves himself. There is still a chest you haven't opened.

i was sure i searched the map well, but befor responding go once again, and find a place where was able to run deep into see, there the ghosts still were. i really run the map several times before. thanks for responding.

no bug.

i did mao kun, there was only 1 chest and i opened no fair graves spawned for me too,
edit: i searched the map for a while and ghosts spawned after a while