[IONIC 4][Android] Keyboard overlaps input in form

In every form of my Android application, the keyboard overlaps the whole screen without making it scroll.
If I try to scroll the entire view manually, nothing changes.
Even adding 300px of fake height to ion-conten, through a div with a fixed height the scroll is locked.
I tried to change AndroidManifest adding the property , but nothing. Also I tried to pass config object to IonicModule.forRoot with the property scrollAssist setted true.

I dont’t understand why I have this bug only in Android app. In iOS everything works fine.
I noticed that the ion-content has --keyboard-offset setted to 0px by :host style.
The code of my view is below:

<ion-content color="primary" padding>

            <ion-icon (click)="back()" size="large" class="top-custom-navigation" name="arrow-back"></ion-icon>

        <ion-col size="12" padding-horizontal>

            <h1>{{'REGISTRATION.WHAT_EMAIL' | translate}}</h1>
            <form #form="ngForm" padding-vertical>

                <ion-label class="small bold uppercase">{{'COMMON.EMAIL' | translate}}</ion-label>
                <ion-input [(ngModel)]="mailExist" #mail="ngModel" name="mailExist" email required
                <div *ngIf="mail.getError('mail') && (mail.dirty || mail.touched)">
                    <ion-label class="error-txt">Mail già presente</ion-label>
                <ion-label class="small bold uppercase">{{'COMMON.USERNAME' | translate}}</ion-label>
                <ion-input [(ngModel)]="username" #userName="ngModel" usernameExist name="username"
                <div *ngIf="userName.getError('username') && (userName.dirty || userName.touched)">
                    <ion-label class="error-txt">Username già presente</ion-label>

                    <ion-col size="9">
                        <p class="small" [innerHTML]="'REGISTRATION.NEWSLETTER_FLAG' | translate"></p>
                    <ion-col size="3" padding-vertical>
                        <app-switch (change)="onChangeNewsletterFlag($event)" style="margin-top:10px;"></app-switch>



    <app-fab-button class="fixed-bottom-right"


are you solved this issue?