Here is code
when we add code with <page-router-outlet></page-router-outlet>
and with using modal after closing modal it make height of
<StackLayout>
<GridLayout [rows]="'*,auto'" columns="*">
<StackLayout>
<page-router-outlet></page-router-outlet>
</StackLayout>
<StackLayout row="1" >
<Tabs></Tabs>
</StackLayout>
</GridLayout>
</StackLayout>
https://play.nativescript.org/?template=play-ng&id=OjBpET&v=9

The above issue happens only in iOS, when the view container ref is not a root view / a page from root frame.
Passing the view container ref injected via app component resolves the scroll issue for now.
https://play.nativescript.org/?template=play-ng&id=OjBpET&v=10
Most helpful comment
The above issue happens only in iOS, when the view container ref is not a root view / a page from root frame.
Passing the view container ref injected via app component resolves the scroll issue for now.
https://play.nativescript.org/?template=play-ng&id=OjBpET&v=10