Uploading a corrupt S/MIME certificate via REST API will complete successfully, however, it will corrupt the user account when trying to edit on the console until you delete the certificate in the Self-Service Portal (SSP).
If you upload an invalid or corrupted SMIME certificate via API, the upload will complete but Administrators will receive an error message if you try and edit the user in the console. Log into the Self-Service Portal as the user and delete the SMIME invalid or corrupted certificate.
This issue has been given identifier FAPI-177815. Our product team has been engaged and is looking to resolve the issue with an update to the AirWatch API.