Inherited users and protected branches

Summary

Hello, we are using Gitlab Enterprise Edition. We tried to protect some branches and restrict merge requests and push access to some users accounts. If the account has been added to the project, there is no problem. However, when an account has rights on a group and it's subprojects, we are not able to add it on protected branche.

The issue exists on both API and UI.

Steps to reproduce

  1. Create a group.
  2. Assign some users to this group.
  3. Create project in this group.
  4. Try to create a protected branche and allow one user to push/merge.

What is the current bug behavior?

API: We got a status 422 Unprocessable Entity.

UI: Page is reloading without effect.

What is the expected correct behavior?

API: We should have a 201 code status.

UI: The new protected branche should appear.

Relevant logs and/or screenshots

{
    "message": [
        "Merge access levels user is not a member of the project"
    ]
}

API result.

proofGitlab

Results of GitLab environment info

Installed on kubernetes cluster through Helm chart.

Expand for output related to GitLab environment info 
Components 
GitLab 11.7.5-ee (ed04633d)
GitLab Shell
GitLab Workhorse v8.0.2
GitLab API v4
Ruby 2.4.4p296
Rails 5.0.7.1
postgresql 9.6.8
Gitaly Servers

Possible fixes

N/A