guild of mystery question

[Phaet]

Trying to join this guild.
I'm supposed to find a treasure map in some ruined house. Been there, found the key to celar, killed 2 monsters there (one ghost and one headless guy), found a treasure chest I can't do anything with (can't interact with chest).
Did I miss something? Can't find any secret rooms there or anything that'd open that chest.

[darkpark]

yeah, it's a little quirky. just go back to the guild and your mission will be considered complete.

[Phaet]

Tried that already. Not working

[swcarter]

The headless guy should have dropped the map.

SWC

[Phaet]

He didn't.
Only his axe and some potions.
Same with ghost: got soul stone.