Dependency proxy is broken: "Error: invalid reference format"

Currently the dependency proxy is broken broken with error:

$ if podman pull -q gitlab.torproject.org:443/tpo/anti-censorship/pluggable-transports//dependency_proxy/containers/alpine:latest; then # collapsed multi-line command
Error: invalid reference format
Unable to pull from dependency Proxy for group 'tpo/anti-censorship/pluggable-transports/'.
The user triggering this pipeline may not have Guest-level permission in that group namespace.
If 'StatusCode: 429' is shown, this means the proxy needed to pull from DockerHub and was blocked by rate-limiting.
(ignore the 'No files to upload' error below).

I have confirmed that the user triggering the pipeline has at least guest permission for the group.