In the ROC you would get the following error while trying to modify the details of an artifact with an artifact type of "Repository": Unexpected error on server [null]. Please refer to server logs with timestamp [2017-12-22 10:44:26].
When reviewing the nolio_dm_all.log file for the timestamp mentioned in the UI error it shows: Artifact Controller Method Error
This is a known defect.
CA Release Automation 22.214.171.12411
CA Release Automation 126.96.36.19907
This has been fixed in the a cumulative patch released for 6.4. Build 188.8.131.5235.
This has been fixed in the a cumulative patch released for 6.5. Build 184.108.40.20635.