I used GeoServer connected to DB with the vector tile extention to export mapbox vector tiles to mapboxGL.
i created a new grid for the 512x512 pixels, because 256 looks too simplify. On zoomlevel 11 the gemetries until 1087 on x-direction looks very bad, but at 1088 it's good (blue is the reference, white the geometry from geoserver).
for me its also not clear why the coordinate system of epsg:900913 beginns and ends at 20 degrees.
Is this an error by the gridset or the vector tile export?