There is a bug with notable locations.
How it should work:
If you research the tech that reveals higher levels locations you can't visit them until you research the tech to raise your adventuring level.
The bug is that the existing notable locations don't update your adventuring level after you research the higher adventuring tech, so they keep saying you need a higher level even if you have it.. they do update when you research the next tier of notable locations though
Workaround: first research the next adventuring level, THEN the next notable locations level.
