Nice map created, but strange cropping

[webbird]

I have used this JSON config to create an SVG:

    {
      "proj": {
        "id": "satellite",
        "lon0": 19.25,
        "lat0": 48.5,
        "dist": 2,
        "up": 0,
        "tilt": 0
      },
      "layers": {
        "background": {"special": "sea"},
        "graticule":{ "special": "graticule", "latitudes": 1, "longitudes": 1, "styles": { "stroke-width": "0.3px" } },
        "countries":{ "src": "ne_50m_admin_0_countries.shp", "attributes": { "iso": "wb_a2", "name": "name" } }
      },
      "bounds": {
        "mode": "polygons",
        "data": {
            "layer": "countries",
            "filter": ["continent", "is", "Europe"]
        }
      }
    }

The result looks really nice, there's a strange cropped area: