The raid completion achievement for killing all bosses on mythic ([Mythic: Castle Nathria]) seems to be missing from the achievement list.

Besides this, the mythic achievement from Shriekwing is also absent from the list, despite it being incomplete ([Mythic: Shriekwing])

Whoops forgot to mark this fixed in (fdee78f)

Thanks, looks like these achievements were a bit weird inside the instance too, with both Mythic and Heroic full clear achievements not accounted for. Also Artificer's Mythic achieve was missing from the general achievements category...