Ionic 4.0 DOM Sanitization Issue-Can't Bind To [href] of <ion-button>

Ionic Framework ionic-v3
1

Had a question and thought that I would post here.

I am working with the latest version of 4.0 and have ran into an issue with sanitizing the DOM.

THIS CODE WORKS
<a slot=“start” clear *ngIf=“OfficeLocation.OfficeLocationPhoneNumber” [href]=“PrepareURL(‘tel:’ + OfficeLocation.OfficeLocationPhoneNumber)” color=“secondary” target="_top" >

THIS CODE DOES NOT WORK
<ion-button expand=“full” [href]=“PrepareURL(‘tel:’ + OfficeLocation.OfficeLocationPhoneNumber)” *ngIf=“OfficeLocation.OfficeLocationPhoneNumber”>Call Us!

Any ideas?