Navmesh has extra areas?

Hi! I’m setting up a plane for simple animation tests and when I bake a navmesh, I get weird islands: Imgur: The magic of the Internet

If I clear the navmesh - the islands remain - how do I remove them?

If you having issue preventing a Nav Path from building in certain areas, you can use a Nav Mesh Modifier Volume component. Place it in areas you don't want nav paths. Select Area Type not walkable.