1. A concise explanation of the problem you're experiencing.
In 2D mode, when you try to use Camera.flyTo on a Rectangle that spans the antimeridian, the camera instead zooms out to span the entire globe. The east/west orientation of the points or the east/west attributes in the rectangle don't seem to matter.
This works fine in 3D mode. Any way around this bug in 2D mode?
4. The Cesium version you're using, your operating system and browser.
Cesium 1.5.5, Windows 10, Chrome 74