Map Completion Impossible
When it comes to new POIs via living story, check to see if you have:
[Second Aetherblade Site] which is just south of [Broadhollow Waypoint] in Gendarran Fields.
[Tower of Nightmares] and [Thunderidge Camp] in Kessex Hills. Both around Viathan Lake.
[Tangleroot Outpost] south west of Brisban Wildlands. This is the entrance to Dry Top.
[Sanctum of Secrets] via [Dead End Cave] in Bloodtide Coast. (An often missed POI even before Living Story)
If you have these, then you need to double-check all the maps which you can do by hovering your mouse of the name of each zone, it’ll show you a pop-up of your map completion for each zone there.
It sounds like you may be missing the Chantry of Secrets. It’s a single poi map within the Order of Whisperer’s hideout within bloodtide coast. Bloodtide coast would show as 100%, but you can still miss this one.
There is also the Dead End poi in the south east section of Divinity’s Reach.
That was added during the Living Story when we first met Margery but you may have missed it if your character had completed Divinity’s Reach before then.
A tip to finding the missing areas once you’ve discovered the zone, using the ‘mouse hover’ technique penelopehannibal mentions is, once in that zone, at the top of the event and quest info on the right-hand side of the screen is the little direction point the game uses to tell you where to go for, say, an undiscovered POI, etc.
If you’ve got everything else in the zone this location finder will show you an undiscovered areas in the zone, which is what helped me a lot last year when like you, I wasn’t 100% world yet had 100% in all zones.