Unable to add new secrets

Since a few days, I’m unable to add secrets in new repos.

It always fails with an error message like this one:

image

While the error seems to indicate the secret is already used, I got this error message with a secret name jsdfhskbdfsbdflabgbgsdjkg which is definitely not used anywhere.
I am, however, able to create new organization secrets.

I’m running latest drone with postgres.