main.py

import kivy
from kivy.app import App
from kivy.lang import Builder
from kivy.logger import Logger
from kivy.properties import ObjectProperty
from kivy.uix.anchorlayout import AnchorLayout
from kivy.core.window import Window

if kivy.platform == 'android':
    from jnius import autoclass, PythonJavaClass, java_method

    _PythonActivity = autoclass('org.kivy.android.PythonActivity')

    class Runnable(PythonJavaClass):
        __javainterfaces__ = ['java/lang/Runnable']
        __runnables__ = []

        def __init__(self, func):
            super(Runnable, self).__init__()
            self.func = func

        def __call__(self, args, kwargs):
            self.args = args
            self.kwargs = kwargs
            Runnable.__runnables__.append(self)
            _PythonActivity.mActivity.runOnUiThread(self)

        @java_method('()V')
        def run(self):
            try:
                self.func(*self.args, **self.kwargs)
            except:
                import traceback
                traceback.print_exc()

            Runnable.__runnables__.remove(self)

    def run_on_ui_thread(f):
        def f2(*args, **kwargs):
            Runnable(f)(args, kwargs)
        return f2

    @run_on_ui_thread
    def go_fullscreen(inst=None, value=None, *args, **kwargs):
        '''Change to fullscreen if we are on a platform that supports it.
        '''
        if kivy.platform == 'android':
            Logger.debug("go_fullscreen: Attempting to enter immersive mode")
            activity = autoclass('org.kivy.android.PythonActivity').mActivity
            View = autoclass('android.view.View')
            decorView = activity.getWindow().getDecorView()
            flags = View.SYSTEM_UI_FLAG_IMMERSIVE_STICKY \
                    | View.SYSTEM_UI_FLAG_FULLSCREEN \
                    | View.SYSTEM_UI_FLAG_LAYOUT_FULLSCREEN \
                    | View.SYSTEM_UI_FLAG_LAYOUT_STABLE \
                    | View.SYSTEM_UI_FLAG_LAYOUT_HIDE_NAVIGATION \
                    | View.SYSTEM_UI_FLAG_HIDE_NAVIGATION
            decorView.setSystemUiVisibility(flags)

    def remove_loading_screen():
        '''Remove kivy splashscreen
        '''
        activity = autoclass('org.kivy.android.PythonActivity').mActivity
        activity.removeLoadingScreen()
else: # not supported. stub out
    def go_fullscreen(inst=None, value=None, *args, **kwargs):
        pass

    def remove_loading_screen():
        pass


class ImmersiveBug(AnchorLayout):
    appinfo = ObjectProperty(None)

    def do_fullscreen(self):
        go_fullscreen()
        self.canvas.ask_update()

    def update_info(self, inst=None, val=None):
        '''Update debug label text'''
        app = App.get_running_app()
        app_info_d = {
            'root.size': app.root.size,
            'Window.size': Window.size,
            'Window.gl_size': Window._win._get_gl_size(),
            'Window.window_size': Window._win.window_size,
            'Window.fullscreen': Window.fullscreen,
            'Window.borderless': Window.borderless,
        }
        self.appinfo.text = '\n'.join(['{}={}'.format(k,v) for k,v in app_info_d.items()])

kv = Builder.load_string('''
ImmersiveBug:
    canvas.before:
        Color:
            rgba: .8,.5,.5,.5
        Rectangle:
            pos: self.pos
            size: self.size
    appinfo: _appinfo
    padding: '50dp'
    BoxLayout:
        Label:
            id: _appinfo
            text: 'refresh to see window data'
        BoxLayout:
            orientation: 'vertical'
            Button:
            Button:
                text: 'refresh'
                on_release: root.update_info()
            Button:
            Button:
            Button:
                text: 'fullscreen'
                on_release: root.do_fullscreen()
            Button:
            Button:
            Button:
                text: 'Update Canvas'
                on_release: root.canvas.ask_update()
            Button:

<Widget>:
    canvas.after:
        Color:
            rgba: .5,.5,.5,.5
        Line:
            rectangle: self.x, self.y, self.width, self.height
            width: 2
''')

class ImmersiveBugApp(App):

    def build(self):
        self.root = kv
        return self.root

if __name__ == '__main__':
    ImmersiveBugApp().run()

p4a command line

p4a apk --name=immersive --private . --version=1 --requirements=hostpython2,kivy,android \
  --orientation=landscape --package=org.learnleapfly.immersive

This was reproduced on a Google Pixel C tablet with android 6.0.1 (Build MXC89L)

Has anyone found a solution to this problem?