For example anchor a UISegmentedControl to the side margins and vertically centre in the view controller and then rotate the emulator.
The same segment is still selected and the font is bold. Just the selected segment color is no longer displayed.
You can see the other segments toggle to bold when selected but still without the selectedSegmentTintColor color.
Inspecting the view hierarchy shows that the UIImageView representing the selected color becomes clear. Trying to set selectedSegmentTintColor to restore the color after rotation does not seem to work reliably - i.e. it works once.
Rotating back and forth does seem in some cases to restore the selected color.