Morphing from 3D to 2D hides vector layers partially

[ezze]

I faced a strange issue I'm able to reproduce in Cesium Viewer:

• load vector data in 3D scene mode (GeoJSON in my case);
• switch from 3D to 2D with morphing;
• you will see something like on pictures below:

When I load vector data in 2D everything works fine.

The problem is reproduced on two diffirent machines with the following characteristics:

1. Ubuntu 14.04 LTS, Google Chrome 49.0.2623.87 (64-bit)/Mozilla Firefox 45.0, NVIDIA GT630M
   
   
2. Windows 7, Google Chrome 49.0.2623.87 (64-bit), Intel HD Graphic 4000/NVIDIA NVS 5400M
   

It also affects some other vector primitives such as billboard and labels in CZML. Probably, this bug is appeared in recent Cesium version (1.19).

GeoJSON sample is here.

[hpinkos]

Thanks for the very detailed write up @ezze! I believe this is the same issue as #3748
This has been fixed in master and will be included in the 1.20 release on April 1st
If you still see this issue after upgrading, feel free to re-open this issue