Footer moved up on app start

I have created an Ionic app to work for Android and Ios.

The issue is with Android that when I open the app for the first time, at the home page there are 3 buttons at the bottom of the page, which moves up (may be due to black bar that comes for 2 secs and go away) and remain there even if I move to other pages and come back to Home page

Please note this issue sometimes comes , sometimes not.

I am just scratching my head and not getting how to avoid such experience.

Any help would be highly appreciated,