<!--IssueSummary start--> <details> <summary> Everyone can contribute. [Help move this issue forward](https://handbook.gitlab.com/handbook/marketing/developer-relations/contributor-success/community-contributors-workflows/#contributor-links) while earning points, leveling up and collecting rewards. </summary> - [Close this issue](https://contributors.gitlab.com/manage-issue?action=close&projectId=278964&issueIid=394736) </details> <!--IssueSummary end--> ### Problem Currently we don't show nor log when a user wasn't mapped correctly during the migration. ### Proposed solution In https://gitlab.com/gitlab-org/gitlab/-/issues/386138#note_1215078523 @georgekoltsov says we could log this info, which would be already step forward. I wonder if and how we could show also this information in the UI (and inform with some message via API).