Sleeper's mask (brown) not appearing as owned in dressing room

[Cimbaeth]

Hello
Just got the achievement nightfall but no reward in the dressing room.

[Starsmith]

Nightfall achievement reward

It looks like something has broken in the awarding of this particular clothing item. We’re looking into a fix. When fixed, we will make sure everyone who has already earned the achievement will get the clothing at that time. Sorry for the inconvenience, and thank you for reporting this!

There’s a fix on the way.