Incorrect tiles from a shapefile are generated by mapnik

[dozzes]

I used mapnik_node_tile_server to generate tiles from a shapefile created by gdal_contour. The tile generation function is:

function fetchTile(layer, z, x, y, callback) {
  var map = new mapnik.Map(TILE_SIZE, TILE_SIZE); // TILE_SIZE = 256
  var layerPath = util.format('%s/layers/%s.xml', __dirname, layer);
  var tileFilePath = util.format('%s/tiles/%s/%d/%d/%d.png', __dirname, layer, z, x, y)
  var cachedTile = getCachedTile(tileFilePath);
  if (cachedTile) {
    callback(cachedTile);
  } else {
    var filePath = util.format('%s/tiles/%s/%d/%d/', __dirname, layer, z, x);
    mkdirp.sync(filePath);
    map.loadSync(layerPath);
    map.zoomToBox(mercator.bbox(x, y, z, false, '900913'));
    var im = new mapnik.Image(TILE_SIZE, TILE_SIZE);
    map.render(im, function(err, im) {
      if (err) console.log('error', err);
      file = im.saveSync(tileFilePath, 'png');
      callback(fs.readFileSync(tileFilePath));
    });
  }
}

Most of contour lines are not rendered in the tiles and transparent areas are not created correctly. Here is the shapefile drawn in QGIS and generated tiles in CesiumJS respectively.

[dozzes]

The reason was in mapnik style xml, I forgot tor remove this line <PolygonSymbolizer fill="white" />