It seems that you are experiencing an issue with duplicate test cases being created in Azure DevOps when adding them to a test case suite without linking them to a user story. This behavior may not be explicitly documented as a known issue in the provided context. However, it is important to ensure that when you add test cases using the grid view, you are not inadvertently creating duplicates due to the way test cases are referenced.
In Azure DevOps, test cases can be reused across different test suites and plans without needing to create duplicates. If you are seeing duplicates, it might be worth checking if the test cases are being added from a different source or if there are any specific configurations causing this behavior.
If this issue persists, it may be beneficial to reach out to Azure DevOps support for further assistance or check the Azure DevOps community forums for similar reports from other users.
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