Ion-checkbox dynamic label

I have an ion-checkbox where I am trying to add a dynamic aria-label but I keep getting these huge [Ionic Warning] console outputs. here is my code:

"@ionic/angular": "^7.3.2"

    <ion-item *ngFor="let friend of friends">
      <ion-checkbox slot="start" [attr.aria-label]=""></ion-checkbox>
      <ion-avatar slot="end">
        <ion-img [src]="getUserPhoto(friend)"></ion-img>

On initial render of the page, I don’t always get this warning, but sometimes. But the friends list is filterable, so the friends array object gets modified and re-rendered. and then the warning appears. Is there any specific attribute I should assign my label to? Ironically, the element printed with the warning has the ariaLabel attribute properly filled out.