artifact expired, download button still available

Our .gitlab-ci.yml has the lines

artifacts:
    expire_in: 1 week

We experimented with the time specification. We set it to 1 min and waited for the generated artifact to vanish. In the view -/jobs/203 there is a Download button. When pressed, a download of 22 bytes is offered - an empty ZIP file. There also is a download button in the view /pipelines?scope=finished for that very job that returns an empty ZIP.

Can you maybe identify if the artifact was purged and not offer a download button?