Data binding problem with ChartJS in Ionic app

Question

In a simple Ionic app I have two components (app-test and app-tracker-chart), one of them uses ChartJs, the other one is a simple list (ion-list) displaying numbers. Both child components use data binding (see [data] in code snippet below) Both components are contained in a parent component (see code below), where the data is being changed with the click event. The component that uses the ChartJS object does not reflect the changed data, the list does.

 <ion-content>
  <app-test [data]="mydata"></app-test>
  <app-tracker-chart [data]="mydata"></app-tracker-chart>
  <ion-button (click)="changeData()">Change Data</ion-button>
</ion-content>

What am I missing here? Is this a bug or is a parameter setting required for the chart? I have created a repository for this problem. BugTestRepo