Protected Branches - "Allowed To Merge" option doesn't work

Version Used: GitLab 11.3.0 (17bd59ad) GitLab Shell 8.3.3 GitLab Workhorse v6.1.0 GitLab API v4

Issue: I would like to strict merges from other branches into develop.

• I've setup a develop as a protected branch with "Allowed To Merge" - no one , "Allowed To Push" - maintainers + developers
• I've used a user which has a "Developer" Role

Steps to reproduce :

• Created a new branch and commit a change
• Performed git merge origin/test_merge_commit
• Performed git push
• Branch protection did not work and a merge happened Merge remote-tracking branch 'origin/test_merge_commit' into develop