Issue Summary

When adding a user as a default reviewer to a repository, the user is added twice. When reloading the page, it looks fine, the user appears only once in the list.

Steps to Reproduce

1. Go to the Repository settings page.
2. Select Default reviewers on the left panel.
3. Add a user to the Default reviewer

Expected Results

When you add a user, the user should appear only once in the list.

Actual Results

When you add a user, the user appears twice in the list. The issue goes away when you refresh the page.

Workaround

Currently, there is no known workaround for this behavior. A workaround will be added here when available