How to display labels with polygon graphics using the entity API?

I am trying to display labels alongside polygons using the entity API. Here's some relevant code:

Sorry for the formatting...

from(Cesium.GeoJsonDataSource.load(data, options) as Promise<Cesium.GeoJsonDataSource>)
                        // Add datasource to cesium viewer - hiding it by default
                        tap(dataSource  => (viewer.dataSources.add(dataSource), = false)),
                        // Add labels / polygon styling
                        tap(dataSource => {
                            dataSource.entities.values.forEach(entity => {
                                entity.polygon.material = Cesium.Color.RED.withAlpha(.3);
                                entity.label = {
                                     text: 'test label',
                                     font : '12px Helvetica',

I can see the polgons fine. But I can't see the labels. I am instantiating labels alongside polylines in a similar manner without any problems. I've also tried using the LabelGraphics class directly and assigning an instance of that class to the entity.label property to no avail.

Cesium version - 1.55
Chrome - Version 72.0.3626.119 (Official Build) (64-bit)

After banging my head against the wall for an hour or two on this one, I've finally figured it out... I needed to set the entity's position manually like this:

    entity.position = Cesium.Cartesian3.fromDegrees(-160, 28);

Thanks for posting your solution! I think what was happening there is that the polygon gets its position directly in the PolygonGraphics object, whereas labels and other shapes like that use the entity’s position.