Slides and backbutton event


I have an application that works with sqlite database and authentication by api of google and facebook with firebase.
When the application enters the login and the user is authenticated, it redirects it to the login. Once this is redirected, it first loads the side menu page and then the screen with the data to be displayed.
In this screen with the data already displayed in the form of cards are displayed perfectly and without problems. Additionally at the top I have an ion segment to change the tabs and this fence changing the card data. The problem comes here and I still can’t solve it.
When I am on the news page and press a segment button it changes the data perfectly. and if after the data loads I press the back button button this minimizes the application since that is the instruction I am giving to this button. But the problem comes when I start the application from scratch and enter the news screen and if I press the backbutton instead of minimizing the application it closes completely.
Any idea why this behavior can happen?