Hello,
Thanks for using the Azure DevOps integration! The object synchronization is intended to be used for requirements (user stories, epics, …). At the moment it is possible to select any issue type to be synchronized to Test Manager but in Test Manager they will show up as requirements. So, using defects as test requirements for testing is something which is not intended. It is more recommended to create an object of different type (i.e. a task) in Azure DevOps which might contain a link to the defect. You could then select this object type for synchronization. This let’s you decide which defects have corresponding requirements in Test Manager.
Kind regards,
Gernot Brandl