Master doesn't appear as first choice in source branch when executing a merge request against GitLab CE

Summary

Master doesn't appear as first choice in source branch when executing a merge request against Git CE

Steps to reproduce

1. Fork GitLab CE.
2. Try to contribute
3. Create merge request.
4. In the source branch type master

What is the current bug behavior?

Master doesn't appear first in the search results

What is the expected correct behavior?

Master should be first right?

Output of checks

This bug happens on GitLab.com