`NORTH` does not list uplad contents, cannot access uploads

[behnle]

Dear NOMAD developers,
i am facing a strange issue with the NOMAD remote tools hub (NORTH).
The NORTH start page launches correctly and lists all tools:

I can also launch tools, but from the started tools, i cannot access my uploads.
The list of uploads is shown in the left

but when an upload is opened, the list is empty.
Furthermore, e.g. trying to create a new text file from the jupyterhub interface throws a permission error:

The shell tool also does not resolve to any actual user name but shows the generic "jovyan" user:

I am not sure if this is the intended behaviour, neither i cannot remember whether this was always the case.

I am running NOMAD 1.3.13 from the mpcfd docker registry:

[root@u-030-s007 nomad]# docker compose ps
WARN[0000] /dockerdata/nomad/docker-compose.yaml: the attribute `version` is obsolete, it will be ignored, please remove it to avoid potential confusion 
NAME                   IMAGE                                                       COMMAND                  SERVICE    CREATED             STATUS                       PORTS
nomad_oasis_app        gitlab-registry.mpcdf.mpg.de/nomad-lab/nomad-fair:v1.3.13   "./run.sh"               app        About an hour ago   Up About an hour (healthy)   8000/tcp, 9000/tcp
nomad_oasis_elastic    docker.elastic.co/elasticsearch/elasticsearch:7.17.1        "/bin/tini -- /usr/l…"   elastic    About an hour ago   Up About an hour (healthy)   9200/tcp, 9300/tcp
nomad_oasis_mongo      mongo:5.0.6                                                 "docker-entrypoint.s…"   mongo      About an hour ago   Up About an hour (healthy)   27017/tcp
nomad_oasis_north      gitlab-registry.mpcdf.mpg.de/nomad-lab/nomad-fair:v1.3.13   "python -m nomad.cli…"   north      About an hour ago   Up About an hour (healthy)   8000/tcp, 9000/tcp
nomad_oasis_proxy      nginx:latest                                                "/docker-entrypoint.…"   proxy      About an hour ago   Up About an hour             0.0.0.0:80->80/tcp, 0.0.0.0:443->443/tcp
nomad_oasis_rabbitmq   rabbitmq:3.11.5                                             "docker-entrypoint.s…"   rabbitmq   About an hour ago   Up About an hour (healthy)   4369/tcp, 5671-5672/tcp, 15691-15692/tcp, 25672/tcp
nomad_oasis_worker     gitlab-registry.mpcdf.mpg.de/nomad-lab/nomad-fair:v1.3.13   "./run-worker.sh"        worker     About an hour ago   Up About an hour             8000/tcp, 9000/tcp

User management is done via a separate keycloak instance (Keycloak 26.1.2) running on a different server.
If necessary, i can also provide you with Docker compose files, configuration files and log excerpts.

The only suspicious log entry i found was
[W 2025-02-24 17:58:56.138 JupyterHub _version:68] jupyterhub version 4.0.2 != jupyterhub-singleuser version 3.1.1. This could cause failure to authenticate and result in redirect loops!

Happy to collect more evidence what might be going wrong here.