When attempting to change the reporter of an issue, if searching with a period or a space (inconsistently) the results will be empty

Issue Summary

Within Jira if you are trying to change the reporter of an issue, if you select the reporter drop down and start typing to filter the list, if you include a space or a period the results will be empty even though there should be matching hits.

This is reproducible on Data Center: (yes) / (no)

Steps to Reproduce

1. Create a user with a full name that includes a space. For example "FirstName LastName" along with an email of "first.last".
2. Navigate to an issue and select the reporter drop down
3. Start typing to filter the list. Type in "FirstName". Notice you should see the list including the user you created.
4. Add then type to search "FirstName l". Notice the list results will drop to 0. This is somewhat inconsistent but happens more often than not.
5. Next search for "first.". Notice as soon as the "." is added the results drop to zero even though it should match on the email address. This is always occurring.

Expected Results

The search should return the filtered users if there is a space or a period in the search term.

Actual Results

If there is a space or period in the search query the resulting user list will no longer be returned.

Workaround

Currently there is no known workaround for this behavior. A workaround will be added here when available. However if you do not include the "." or the "space" character in the search the results will appear based on the stem word.