The Teams Mobile speed dial doesn't show names only Numbers

For about a week now, we have had the problem on several Android phones that all external numbers are no longer displayed in the Speed dial in the Teams app.
The contacts are created and available online in the web app and can also be seen there, but in the mobile app you can only see the numbers.
However, if you click on the number in the mobile app and display the “Profile”, the name is also displayed.