When rendering point geometries, regardless of passing in fillOpacity and fillColor to the vectorTileLayerStyles function, it seems to render the points as circlemarkers with no fill at all:

The code to get this follows the docs pretty closely:
  L.vectorGrid
    .slicer(geoJsonGoeshere, {
      rendererFactory: L.canvas.tile,
      vectorTileLayerStyles: {
        sliced: function (properties, zoom) {
          return {
            radius: 5,
            color: properties.daqi.color,
            fillOpacity: 1,
            fillColor: properties.daqi.color
          };
        }
      }
    })
    .addTo(map); 
Sandbox demonstrating the issue
Is this a known bug?  Am I doing something wrong?  This seems to be the case for both canvas and svg renderers.