REST API v4 JSON /projects/:id/approvals not updated after updating project's MR Approval configuration via WEB UI

GitLab EE version 11.11.1-ee

YUM package gitlab-ee-11.11.1-ee.0.el6.x86_64

Scenario

I log on to our server web UI with a user having Administrator permissions.

I go to my project's root blabla/subproject/my_project : I am owner of this project.

I navigate to my project’s Settings > General and expand Merge request approvals, and define some users and groups as approvers.

I set the No. approvals required parameter to 2.

I save my changes, and now browse with Firefox to my.gitlab.server/api/v4/projects/<my_project_id>/approvals.

THE JSON HAS NOT BEEN UPDATED, and does not reflects my changes, it displays my old config already present prior to upgrading to 11.11.