Merge request pipeline status is not updated

Summary

https://gitlab.com/gitlab-org/gitlab-ce/merge_requests/13959 displays a green pipeline (https://gitlab.com/gitlab-org/gitlab-ce/pipelines/11337470) which is for 9e9b439e. However the commit that got merged is e7817fc1 which had a failing pipeline (https://gitlab.com/gitlab-org/gitlab-ce/pipelines/11334658).

This happened while gitlab.com was on 9.5.2-ee (65f8414c).

Steps to reproduce

sorry, I don't know

What is the current bug behavior?

merge request displays passing pipeline and could be merged

What is the expected correct behavior?

merge request displays failing pipeline of the commit that got merged

Screenshot