Bug with primitive label + columbus view + relativeToGround

Cesium1.78 - After I created a primitive label with heightReference=relative_to_ground in columbus view, I tried to update the position but the label got height and was fixed only after playing with the zoom level (I have noticed that there was a wrong _actualClampedPosition that was fixed after playing with zoom level)

any idea?

code:

ezgif-4-077167462d29