ionic 4 virtual scroll not setting height inside container

Ionic Framework
1

So, I have created a layout for a page which contains a Header and a button, and below an ng-container in which the ion-virtual-scroll is being rendered. However, the last elements are not being displayed because I can’t scroll to their location, but if I delete all the remaining elements on the layout then every element on the ion-virtual-scroll are visible.

this is the layout template:

<ion-header>
    <ion-toolbar>
        <app-header [name]="name" [avatar]="avatar"></app-header>
    </ion-toolbar>
</ion-header>
<ion-searchbar (ionChange)="emitValue($event.detail.value)"></ion-searchbar>
<ng-content></ng-content>

and this is the scroll template:

<app-page-layout (searchValue)="filter($event)">
  <app-notification-actions
    (sortNotifications)="sort()"
    (addNotification)="create()"
  ></app-notification-actions>
  <ion-content >
    <ion-virtual-scroll [items]="notifications" approxItemHeight="154px">
      <div *virtualItem="let notification">
        <app-notification-card [data]="notification"></app-notification-card>
      </div>
    </ion-virtual-scroll>
  </ion-content>
</app-page-layout>