After adding a new commit to the existing merge requests, the update time of this merge request has not been changed

I have an issue with upadting the update time of a merge request. The create time and update time are the same for a merge request. But this merge request has a commit that was added after time creation of the merge request. It is a floating bug. Sometimes GitLab changes update time after adding a new commit to a merge request.

I’ve provided API responses responses for this merge request where you can see that creation time and update time of the merge request are the same but a commit in this merge request has been added after creation time of the merge request.
“id”: 79242532,
“iid”: 2,
“project_id”: 22656430,
“title”: “WWW”,
“description”: null,
“state”: “opened”,
“created_at”: “2020-11-24T05:06:28.330Z”,
“updated_at”: “2020-11-24T05:06:28.330Z”,
“merged_by”: null,
“merged_at”: null,
“closed_by”: null,
“closed_at”: null,
“target_branch”: “master”,
“source_branch”: “test2”,

“id”: “e23d1fc9032a79e591f7550764f6f6793b8e100a”,
“short_id”: “e23d1fc9”,
“created_at”: “2020-11-24T05:07:00.000Z”,
“parent_ids”: ,
“title”: “TST-1 Update”,
“message”: “TST-1 Update”,
“committed_date”: “2020-11-24T05:07:00.000Z”,
“web_url”: “
}, {
“id”: “23585889d23814e568c112e1d2caefc56afe0633”,
“short_id”: “23585889”,
“created_at”: “2020-11-24T05:05:22.000Z”,
“parent_ids”: ,
“title”: “Update”,
“message”: “Update”,
“committed_date”: “2020-11-24T05:05:22.000Z”,
“web_url”: “