When trying to add users to a repository, some users will not show up in the list although they have valid Bitbucket accounts.

Steps to reproduce

Go to https://bitbucket.org/<username>/<reponame>/admin/access.

In the user field, start typing a username or email address.

Expected result

The username you're looking for will show up in a list so it can be selected.

Current results

Some users that have been verified to have a Bitbucket Cloud account don't appear on that list. However, if you type the whole username and press enter, the user will be added to your repository.