Load the attached save. In the geoscope, klick "show radar range". There is an UFO over North America. Klick onto the corresponding "UFO button" in the top left so that the geoscope view centers onto that UFO. This causes the radar ranges to disappear (which was not the case in 2.5).
It also happens for a lot of other actions, the view entering and leaving a base for instance. This is just the easiest way to reproduce I found.
2.6-dev built from git@20e5d1df0c9340977c46d866a46f8c8ae8636410