Get the number of triangles of the tiles in the tileset

Why do I use the code to get the number of triangles of the tiles in the tileset, but the first few tiles show a value of 0, but when I look in the 3D Tileset Inspector, I find that the tiles that show 0 have a triangle number of not 0

tileset.tileLoad.addEventListener(function (tile) {
                console.log("Tile loaded:", tile.
                    _contentHeader.uri);
                console.log("Triangles in tile:", tile.content.trianglesLength);
                console.log('-----------------------------')
            })

The 3D Tiles inspector does not show the number of triangles of a single tile. As mentioned in the other thread: It shows the number of triangles that are currently displayed. (Depending on many technical details of the structure of the tileset, this may include triangles that are not visible on the screen).

There certainly can be tiles that have no content (and the trianglesLength will be 0 for them).

thanks