(bug) Vista oversight
In the first dungeon where you have to turn the power on and at the end the bridge goes up to let the walker go over the last vista in this dungeon is on the bridge which leaves the dungeon. This means that if you do not view it before you raise the bridge the vista is lost to you forever.
As you can see the dungeon is missing the vista because it is on the bridge outside the dungeon.
Bit of an oversight but i hope a patch comes soon.