At @mentions not working correctly

Summary

Issue with (at) @ mentions when attempting to add comment for user. @mentions only populates with user's lastname and (not firstname) on 1st attempt. Issues is intermittent but reproducible.

Environment

JIRA CLOUD
7.0.0-OD-07-011JIRA CLOUD
Chrome: Version 45.0.2454.101 (64-bit)

Steps to Reproduce

1. Log into Instance > Open any issue and click Comment
2. Type @ and 1st 3 letter of firstname > User doesn't show up.
3. Remove text, try again. Type @first 3 letters of lastname > User comes up
4. Remove text, try again. Type @first 3 letters of firstname > user now comes up

Expected Results

User to come up with @mention with both firstname and lastname on the first try.

Actual Results

User doesn't show up with firstname only with last name on first attempt.

Notes/Comments

If page is refreshed the same issue will occur and user will need to type in @lastname again for @firstname to work.

Was able to reproduce in both IE and Firefox as well.

Workaround

Type @lastname in comments for user to show up. Once user shows up you can type @firstname and user will show up in dropdown list.