There is an incompletable Quest in the Revendreth section.

The quest Forgotten Village is actually a Bonus Objective rather than a quest. Bonus Objectives cannot be completed once a player reaches level 60.

As a solution, this Bonus Objective could be removed from the Revendreth Quests or a new filter added to the Unobtainables section to allow it to be removed.

Quest: Forgotten Village
Wowhead Link: https://www.wowhead.com/quest=59211/forgotten-village

Still haven't heard of anyone finding a way of obtaining this quest, but for now it is at least considered 'locked' once the player reaches level 60, so it will hide itself from the list unless 'Locked Quests' are tracked. Will close this issue since the original intent has been addressed.

Can confirm - noticed this as well after finishing all the other quests in the zone
I believe there is one also in maldraxxus, "Avoid 'em like the plague"
Says only a toon that chose to skip the storyline can collect this..
Not sure if this belongs there since it can't be done at this point unless you do it on an alt

'Forgotten Village' (59211) is just missing the necessary data to indicate its proper collection requirements (if it's a bonus objective it can only be completed by a 'Skip' character). Once this data is determined and added it will show/hide correctly based on the current character.

'Avoid 'em like the plague' (62742) is correctly set up, and would only show on a 'Story' character due to the collectible appearance currently listed for this bonus objective. That may be removed if it becomes apparent that it is variable in what the reward is for this objective.

Additionally, we may need to put a level range of 48 - 59 on most bonus objectives if they are removed once hitting level 60.

Bonus objectives can be completed by level 60 characters using Party Sync, I check with my level 60 character using Party Sync, and Legion Bonus objectives appeared on the map. So I think for this type of quest there should be added the maximum level range in the addon so it disappears for level 60 characters.

For those who want to complete all these quests, the option could be to add it to the Breadcrumb option in the UI because after all that option what do is hide quests that can't be completed without Party Sync when is unchecked.

This Quest has recently been tagged as a 'Breadcrumb' and assigned a level range of 58-59 and a required Source Quest (according to unverified Wowhead comments), but we still have yet to have any verification of what criteria is specifically necessary to acquire this bonus objective, or if it is possible to complete via Party Sync.

People have shown proof of completing it though, so there is some qualification that makes this possible, we just don't know what it is yet.