changing the model does not trigger resize

[aircable]

In my case, the app writes to the ngModel that is linked to the fz-elastic textarea. When doing so, the resize event it not triggered. It is only triggered when input field it used.
It should scroll to the last character, but it does not.

[aircable]

Sorry, I should be more clear:

template:

<ion-item><ion-label floating>Terminal</ion-label>
    <ion-textarea fz-elastic  [(ngModel)]="terminal"></ion-textarea>
</ion-item>

code:
this.zone.run(() => { this.terminal += this.newLIne; });
behaviour:
Even though the screen gets updated, when full, the content does not scroll to the last line (or entry). Every following line added is therefore invisible.
expected:
The last string concat to the textarea should be visible at the bottom of the text field. Previous content should be scrolled up, the same way as a manual entry inside the textarea.
The ngZone should trigger the resize after it has been changed.