Polygons in different layered tiles are not connected when they are in the input mesh

The same geometry used for layered and not layered tiles gives different navmesh structure. If it's a single tile, polygons are properly generated and it's possible to find a path. If the same geometry is divided between 2 layered tiles, they are not connected and findPath provides only partial result. Here is the test demonstrating the problem. Basically I generate a slope-like mesh in a way that only a part of it should belong to both tiles and add 2 tiles at different adjacent layers with overlapping bounds. IIUC these 2 function calls are supposed to connect them but they don't and it's unclear what is the case when they do.