@Mark Admin, Thanks for posting in Q&A. From your description, it seems one user is unable to login Teams on one affected device but can login another personal device with the same user account. If there's any misunderstanding, feel free to let us know.
For the affected device, it is re-enrolled. Please try the following suggestions to see if it can be fixed.
- Please delete the device in both Microsoft Entra and Microsoft Intune.
- Reset the device and enroll again.
- Try to login Teams on this device to see if it can login successfully.
However, if the issue persists, please check the sign in log to see if we can get more finding.
https://learn.microsoft.com/en-us/entra/identity/monitoring-health/concept-sign-ins
Hope the above information can help.
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