Why camera sensor fit auto,horizontal and vertical FOV different in resolustion x<y?

Theoretically when resolustion x>y(horizontal photo) it should selet horizontal of sensor fit, auto fov = horizontal fov. when resolustion x<y(vertical photo) it should selet vertical of sensor fit, auto fov =vertical fov. but In fact when resolustion x<y auto is diffrent vertical fov, there is 3 fov! why? Is it a code error?image