I have researched the ability to adventure into notable locations at level 3. The map shows all level 1 to 4. If I have researched level 2 - the map shows level 1 to 3.

I can only assume that this is a bug, as locations that I cannot visit serve no purpose other than to be annoying to the user, as I accidentally trip over them. At any rate, it makes no sense that I am able to see the location, but unable to visit it - especially as these notable locations tied to my adventuring level are "loot only" and pose no challenge.

Expected result is that new locations of level X become available as I have researched the ability to visit locations of level X.