I have a similar issue. It's triggered the same way. I'm using a third party launcher (nova launcher) for me the recent app screen sticks when there isn't any apps running . I contacted nova and they said its and issue with the Asus launcher and Android.
I can get out of the screen by swiping down the notification bar and then swiping the home screen or menu. At least it avoids a whole phone reboot.
Like zt959595 said the temp solution is to just keep something open.
This bug is even worse for me. Pressing the recent apps button just does absolutely nothing (not using gestures, Nova launcher). Holding the button takes a screen shot so something is working.
How are updates this broken even released? Does no one there even try to basic function test anything?