Same. No Adept Hunter Achieve. Box is empty. Says it's missing MMM. But, i completed MMM on 8/9/21, and the MMM box is checked. Same thing on all my 4 chars on Bristlebane. Rather not petition a bunch to get it fixed.
Because they have been adding/removing targets to achievements, it breaks the script updating the overall one and you have to petition to get it fixed. Attach a screenshot of the completed and the one missing the checkmark and it will be fixed. You can petition from one account to have multiple accounts/characters fixed.
They added Findlewill to the August patch and it actually got checked even without killing him, just go kill Findlewill and it will fix its self.