Problem with Microsoft Teams Shifts App (Username has changed - in shifts App will be the old name displayed

This is a German-language forum; however, since you've asked your question in English, please allow me to respond in English as well.
Hi @Kaiser Alexander, 

Thank you for reaching out, and I understand how important it is to have the correct display name reflected in Shifts. 

In general, name changes made in Microsoft Entra ID are propagated to Microsoft Teams through a background synchronization process. Typically, this can take some time to fully reflect across all Teams components. However, in some scenarios, certain areas (such as Teams apps like Shifts) may continue to display the old name due to caching or delayed backend updates. 

Based on similar cases, even if other services (Teams, Exchange, Entra ID) already show the updated name, it may take additional time for all Teams experiences to fully align. In some situations, the update doesn't not sync correctly due to service-side caching or indexing behavior. 

Since you have already performed key troubleshooting steps (such as clearing cache and re-adding the user), and the issue still persists, this could indicate a limitation or delay beyond normal sync behavior. 

If the issue continues, I would recommend monitoring it for 24 hours. If there is still no change, the next step would be to raise a support request so that the backend sync and Shifts data can be checked more closely. 

To resolve this issue, Microsoft’s support team will need to be engaged. A technical support engineer can conduct a remote session to investigate the situation, verify backend configurations, and run any required synchronization tools. Since this case will likely involve collecting and analyzing logs, it is recommended to raise a support ticket to ensure a smoother and more efficient resolution process. 

The Global Admin should create a service request with Microsoft support to get advanced technical assistance and diagnostics. For detailed instructions on how to get support, please refer to Get support - Microsoft 365 admin.     

As community moderators, I don’t have access to internal service logs, backend diagnostics, or engineering dashboards due to privacy and security restrictions. Issues that may involve backend or service related problems can only be fully investigated and resolved by Microsoft’s product engineering teams.  

Thank you again for your time and understanding. I really appreciate your patience, and I’m here to help. Looking forward to your response.

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