If you can capture some screenshots or even a video will be best.
Sometime the achievement update is delayed, could be days!
You may try the followings to see if they will trigger a update:
- try switching to other region and back.
- if you have other achievements to be completed, go for them first, check this achievement afterwards.
If other achievements don’t show up as well, then probably something blocks the update. Likely a technical issue than a bug. Will discuss later if this is the case.