Search list incorrectly shows no results after selecting a user

In the new enrol users control, if I search and see a list of users, then select one of them, I would expect the search results to continue to show the other users (or at worst some message saying I had to search again). What actually happens is that the search results disappear and a message saying "No suggestions" is shown.

This appears to happen only when the search matches on email - when matching on name it works as expected.

So, to reproduce:

1. Create ten users: Person One (user1@example.com) etc
2. Go into participants in a course and click "enrol users"
3. Search for example.com
4. Select one of the users
5. The search results are replaced with a "no suggestions" label