Testing on android device:
1 - Open game. It is shown in fullscreen landscape.
2 - minimize game and open something in portrait mode.
3 - Go back to the game. The orientation is still landscape but the screen is cropped.
4 - If I turn around the phone the screen gets fixed.
This happens on my games and on the openfl demos BunnyMark and SimpleSWFLayout.
I tested old games that were published using openfl and the problem was not present.