PointPrimitives display problem- Cesium 1.17

I am seeing some weird visual effects when I try to display an autzen.las pointcloud file in Cesium. I made a video which shows the problem: https://youtu.be/7NoD88Ui_zs
The code I’m using for this video is below (with Cesium 1.17):

var pointPrimitives = rMap.map.scene.primitives.add(new Cesium.PointPrimitiveCollection());
for(pointsIndex;pointsIndex<arr.length;pointsIndex+=3){
pointPrimitives.add({

position : new Cesium.Cartesian3(arr[pointsIndex], arr[pointsIndex+1], arr[pointsIndex+2]),

color : new Cesium.Color(colors[pointsIndex]/255, colors[pointsIndex+1]/255, colors[pointsIndex+2]/255, 1),

outlineColor: Cesium.Color.BLACK,

pixelSize : 1.0,

show: true

});
}

``

Previously we used the PointGeometry from Patrick’s old branch referenced here which displayed fine at all viewing anbles: https://groups.google.com/forum/#!msg/cesium-dev/20B0jNK7I4U/-sy5kmEdSPwJ

var myPoint=Cesium.Cartesian3.fromDegrees(-75.59777, 40.03883);

var typedArray = [ myPoint.x, myPoint.y, myPoint.z];

var pointInstance = new Cesium.GeometryInstance({

 geometry : new Cesium.PointGeometry({

   positionsTypedArray: typedArray

 }),

 id : 'point',

 attributes : {

   color : new Cesium.ColorGeometryInstanceAttribute(0.0, 1.0, 1.0, 0.5)

 }

});

scene.primitives.add(new Cesium.Primitive({

 geometryInstances : [pointInstance],

 appearance : new Cesium.**PointAppearance**()

}));

``