Coverage of pipeline is not shown on merge_request page, but can be extracted via API

Summary

If I posted commit status coverage via commits API, pipeline with external job is created and shown on merge request page, but without coverage field

Steps to reproduce

1. Post data using commits API commit status for last commit in merge request:

POST /api/v3/projects/:project_id/statuses/:sha?state=success&coverage=33.2&name=Coverage Report

result is 200 OK; pipeline and external job also created.

2. (just to verify) GET /api/v3/projects/:project_id/pipelines/:id

see result like

{
  "id": 10524, 
  ...
  "coverage": "33.20"
}

What is the current bug behavior?

Go to merge request url

See pipeline with success status but without coverage field

What is the expected correct behavior?

See pipeline with success status with coverage field

as stated on this page https://docs.gitlab.com/ce/user/project/pipelines/settings.html#test-coverage-parsing

In addition I want to say that badge (https://docs.gitlab.com/ce/user/project/pipelines/settings.html#test-coverage-report-badge) displayed correctly.