Skeleton Mask?

[Yiab]

I've got nearly everything in the game finished, but I can't find the skeleton mask.
I'm only missing 4 feats:
have 1,000,000 coins
collect every artifact
die 10 times
achieve every other feat

Obviously I can see how to get 1,000,000 coins (sell lots of stuff) and die 10 times (get killed by demons repeatedly), but how do I get the last artifact - the skeleton mask?

Edit: Does it have something to do with the guy who just says he doesn't like me and asks me to go away?

[Tornadodex]

Actually, you have a chance to find it in any large chest. Are you sure you've opened ever chest? To check, go to "Gear" and look at the top left. If you've opened all 46 chests, you should have found it...

[Yiab]

https://steamcommunity.com/sharedfiles/filedetails/?id=1726756327
Yup, it says 46/46 and I still have no skeleton mask.

[CayCay]

I am having the same issue, but for me it's the Holy Relic. Bumping to try and bring more awareness to this issue.

[zoning.x]

I have also encountered this bug on switch version.
If I want to get skeleton mask, need to be game over?

[NialEra]

same problem here u.u any solution?

[anpollaci]

I have the same exact problem. Any solution that you came up with?

[Azmodeun]

Have you made sure you completed the ghost npc in the frozen biome? He drops a chest I believe.