Ion-icon attribute "name" does not work, "icon" does

Ionic Framework
1

I just tried to fix a strange bug:

I have an item with an icon like this:

<ion-item>
      <ion-icon name="{{iconname | icon}}" *ngIf="iconname" slot="start"></ion-icon>
      <ion-label class="ion-text-nowrap more">
        NAME
      </ion-label>
</ion-item>

This does not work, but if I change name to icon it works.

<ion-item>
      <ion-icon icon="{{iconname | icon}}" *ngIf="iconname" slot="start"></ion-icon>
      <ion-label class="ion-text-nowrap more">
        NAME
      </ion-label>
</ion-item>

The app is using Ionic 4 and Angular. Does this happen because of the use of Angular template variables?