In editing screen of pull request, I tried to add more reviewer by typing "@ kim" but it doesn't bring any list of my teammates.

Fortunately the reviewer is in recent list, so that I can put her into reviewers. But auto completion still does not working. It worked well on last week.
When I checked API call, it tries with following url, https://bitbucket.org/xhr/mentions/repositories/36sprints/poclcast?term=%40kim
But got empty list response with 200 return code.
Is this correct behavior? or some bug in bitbucket?