Kiosk mode is not maintained on older Android devices

When the application goes into the background and later reenters foreground, Kiosk mode is not maintained and the menu bars and navigation buttons come back. (Nexus 5 - Android 6.0)

This is not an issue on newer devices.

If I exit kiosk mode when suspended and the enter it again on resumed, it’s possible to keep it fullscreen, however this is quite a jaggy experience.

I implemented a solution here, that works
(however it’s not clear where to send the signed Contribution license agreement to actually have it merged):

Any tips would be appreciated.