Project export api returns incomplete json missing api_url and web_url

Summary

The project export api returns export_status: finished but is missing the _links property.

Steps to reproduce

When calling the project export api status endpoint GET /projects/123/export sometimes the result doesnt contain api_url nor web_url.

What is the current bug behavior?

{"id":123,"description":null,"name":"My Project","name_with_namespace":"acme / myproject","path":"myproject","path_with_namespace":"acme/myproject","created_at":"2016-07-04T15:03:55.722Z","export_status":"finished"}

What is the expected correct behavior?

{"id":123,"description":null,"name":"My Project","name_with_namespace":"acme / myproject","path":"myproject","path_with_namespace":"acme/myproject","created_at":"2016-07-04T15:03:55.722Z","export_status":"finished","_links":{"api_url":"https://gitlab.com/api/v4/projects/123/export/download","web_url":"https://gitlab.com/acme/myproject/download_export"}}

Output of checks

This bug happens on GitLab.com