When the Window's softinput_mode is set to 'below_target' or 'resize', the Window size and position is not correct after requesting keyboard with textinput/restartting the app after first launch.
Example app code:
https://gist.github.com/rafalo1333/5484ebdba49203074114
App UI on initial launch:

App UI when keyboard was requested (look at the bar under the TextInput widget:

App UI after hiding keyboard/resetting the app (look at the bar under the TextInput):

With the Window.softinput_mode set to 'resize', things are going even uglier.
It could be related to #483 PR.
It should be fixed as right now Kivy TextInputs are unusable on Android.