Supposedly, Fixed scan buttons exist even in any rotation.
Actual behavior
When I go into the Radar feature and do the scanning, And accidentally change the rotation into landscape, suddenly the scanning button is gone. I guess it's just a coincidence, but after I repeat it the same thing happens.
How to reproduce
Install and open the app (make sure you turn on Bluetooth)
Next click the radar feature, and do scanning by clicking on the icon located at the right bottom of the application.
When scanning, change the rotation to the landscape