Ion-select not working in iOS

Hi, I’m trying to make a multiple select box of countries in Ionic 3.1.1, it works fine on Android, but on iOS, clicking the ion-options doesn’t actually select the boxes. (They stay empty no matter how much you tap them)

My HTML is:

<ion-item no-lines>
  <ion-label fixed narrow>Region</ion-label>
  <ion-select formControlName="region" (ionChange)="region_change($event)" multiple="true">
    <ion-option *ngFor="let r of regions" value="{{ r }}">{{ r }}</ion-option>
  </ion-select>
</ion-item>

In my Constructor I have:

this.form = form_builder.group({
  region: [''],
  city: ['', this.validate_city],
});

region_change is:

region_change(regions) {
  this.city_bar.clearValue();
  this.region_provider.set_filter(regions);
}