Navbar overlap with content

There are page A and B. Page A has a list who navigates to B. B has some input fields.
If I edit the fields and USE hardware back button(Android) to back to Page A. The title
and the list overlap.

html file

    <ion-navbar >
            The Title
<ion-content  style="background-color:#f2f2f2;">
    <ion-list  no-lines   >
        <ion-item *ngFor="let t of shortTrain">
            <h2 >{{}}</h2>
            <p style="font-size:12px;">{{t.subtitle}}</p>
            <p style="font-size:12px;">
                <button ion-button color="secondary" round item-end (click)="toSignUpInfo(,,t.trainTime,t.deposit)">Click Me</button>


Use software back button on the navbar works ok.

Any one could help me? Thanks a lot.