Provide unique values from a user profile field in a content type field (How to use DISTINCT in ER View)?
Try using aggregation. Set this value in your View under Advanced > Use aggregation. The Group Results Together aggregation type should be the default and should provide the behavior you're looking for.

If this isn't quite what you're looking for, please export a copy of your view configuration, from Configuration > Development > Configuration synchonization > Export, then select Single and find your view under the Views dropdown and update your question with this export.