There's a regex pattern in https://github.com/vsoch/oci-python/blob/master/opencontainers/distribution/reggie/defaults.py#L17
that doesn't properly escape the / characters. It's unclear to me at the moment what's changed (other than python updates) have have caused this to be an issue in particularly for Authentik.

I'm not quite clear on the preferred contribution method here, but I'll at least fork and create a PR for this change and see if that's helpful.