NavMesh Surface in ARKit

Hi there,
I am trying to dynamically create a navmesh by a script, I have a plane which is created dynamically and it's position is constantly updated. I add the navMeshSurface component and build the navMesh, however it's empty. Looking through it using the NavMeshTriangulations I see the vertices and triangles are 0. The dynamically created object has a plane mesh (mesh filter) and that mesh has real values for vertices and triangles, when this plane mesh is used to generate a navmesh it doesn't work as I get 0 triangles and vertices. Note the dynamically created object has a scale of less than 0, Does this affect it? Also this is in ARKit so does this affect navmesh surface as the plane is found dynamically and then the navmesh surface builds it dynamically/