WindowManager.addView() - "Unable to add window - token null is not valid; is your activity running?"

Firebase Crashlytics reported one device (Xiaomi Redmi 4X, Android 7.1.2) with error at (I can't reproduce this issue on my own devices)

fun show() {
    if (Settings.canDrawOverlays(context) {
        windowManager.addView(floatView, layoutParams)
    }
}

Caused by android.view.WindowManager$BadTokenException Unable to add window -- token null is not valid; is your activity running?

override fun onStop() {
    super.onStop()
    if (prefsManager.isShowOverlay()) {
        floatingWindow.show()
    }
}

My apps shows the floating window when activity stops (Activity.onStop()), here's logs from crashlytics:

p.s. please don't reference here similar questions but for AlertDialog and PopupWindow, it's a different issue!