In android 4.4 and higher we use what's called "immersive screen". See
https://developer.android.com/traini...m-ui/immersive.
That's it: we always run in fullscreen mode, except when the user makes a swipe gesture to show UI bars.
Are you sure you're running the same firmware now and in the summer?
If you're not sure you might want to try older versions again, because they should behave exactly the same.
In any case we can't do nothing without logs, which you can get with adb and the following command: