Deleting certificates on updated systems throws an error

I don’t know if this error has anything to do with this topic. Today I wanted to delete a requested certificate that I no longer need. When I delete it, I get this error message.

JSON Schema output validation aborted at step /home/traefik1/.config/actions/delete-certificate/validate-output.json: JSON unmarshal error: unexpected end of JSON input. Input data: [ ]

After refreshing the page, the certificate is no longer displayed, but the certificate is still present in the file /home/traefik1/.config/state/acme/acme.json.

How can I permanently delete the certificate?

Best, Erwin