Nav Mesh appears over objects during runtime

I am making a VR game and using the assets from Polygon Sci-Fi city. I want to create some AI characters and i’ve followed some tutorials for a simple AI, however, the AI when they should be working they stand still. I noticed that my Nav Mesh wasnt working properly as during runtime it appears higher than it should be (like the attached pictures). I think this may have to do something with the collision of the meshes but I am not sure yet. I’d appreciate any help as i am quite new to game development. Thank you!.