Cannot override `updated_at` when updating Issue via API

Summary

When editing an issue via the API, e.g., changing labels, assignee, or state, updated_at is always set to the current time, even if a specific time is passed via the updated_at field.

This is probably related to #40454 (moved).

Steps to reproduce

Send a PUT request to an issue that includes setting update_at:

For example, I do

curl --request PUT --header "PRIVATE-TOKEN: token" \
  https://gitlab.com/api/v4/projects/6537394/issues/2?state_event=close&updated_at=2016-03-11T03:45:40Z

curl --request PUT --header "PRIVATE-TOKEN: token" \
  https://gitlab.com/api/v4/projects/6537394/issues/2?labels=label&updated_at=2016-03-11T03:45:40Z

curl --request PUT --header "PRIVATE-TOKEN: token" \
  https://gitlab.com/api/v4/projects/6537394/issues/2?assignee_ids=2331657&updated_at=2016-03-11T03:45:40Z

Example Project

Here is the issue that I tried to update with the previous calls: https://gitlab.com/svigerske/updated_at-ignored/issues/2

What is the current bug behavior?

The issue modification steps are listed as "a minute ago":

What is the expected correct behavior?

The issue modification steps should be listed with date 11th March 2016.

Relevant logs and/or screenshots

See above.

Output of checks

This bug happens on GitLab.com

And also with my installation of Gitlab CE omnibus.

Results of GitLab environment info

Gitlab.com

Results of GitLab application Check

Gitlab.com

Possible fixes