Filter issues input does not show assignee name when there is an assignee ID in the URL

If you have an assignee id in the URL, the filter input does not show the assignee name like it used to.

I have my issues bookmarked filtered by the current milestone, if I open the link I don't see my name in the assignee - which is not a problem - but if I delete the Milestone and hit enter I also loose the assignee filter.

Steps to reproduce

1. Open this link https://gitlab.com/gitlab-org/gitlab-ce/issues?scope=all&state=opened&utf8=%E2%9C%93&assignee_id=482476&milestone_title=8.16
2. Clear the milestone and hit enter
3. Issues are no longer filter by assignee