Gitlab Issues: updated_at field not changing for Gitlab 10.4/10.5

This is a problem I saw in Gitlab Community Edition 10.4.4/10.5.0 but not 9.5.0/10.0.0 The updated_at field for Issues is not changing the majority of the time when I add comments or change assignee. Below are steps to reproduce

Adding comment to issue

  1. Create an issue
  2. Check updated_at field at endpoint /api/v4/projects/{id}/issues/{iid}
  3. Create a comment on the issue
  4. Check updated_at field at endpoint /api/v4/projects/{id}/issues/{iid}

Expected: updated_at field has changed
Actual: updated_at field does not change

Changing assignee for issue

  1. Create an issue
  2. Check updated_at field at endpoint /api/v4/projects/1/issues/{id}
  3. Change the Assignee for the issue
  4. Check updated_at field at endpoint /api/v4/projects/1/issues/{id}
  5. Change the Assignee for the issue again
  6. Check updated_at field at endpoint /api/v4/projects/1/issues/{id}

Expected: updated_at field has changed
Actual: updated_at field does not change

Setup:
Gitlab Community Edition 10.5.0
API v4

Since other people will likely run into this it looks like Gitlab now throttles how quickly the updated_at field can be changed