400 invalid request, when search for issues and merge request in ie 11

Summary

When sending the search text entered in the search-box on open issues/merge requests to the server at https://gitlab.com/gitlab-org/gitlab-ee, ie 11 shows a message the the browser sent an invalid request.

Steps to reproduce

1. Open IE 11
2. Got to https://gitlab.com/gitlab-org/gitlab-ee
3. Enter text to search for in open issues
4. Press Enter -> results in 400

What is the current bug behavior?

Browser shows:

400 Your browser sent an invalid request.

What is the expected correct behavior?

Filtering the issue/merger request list by the entered text.

Relevant logs and/or screenshots

IE Version: 11.0.9600.18537 Updateversion: 11.0.38

No error reported on IE console.