Unknown collections appearing

I have deployed radicale container as internet-facing service, behind https nginx reverse proxy. During routine backup and reboot, I noticed the container is complaining about being unable to change ownership of files. The file names seemed weird to me, so I went into the NFS-bound volume of the container and inspected the `/data` directory content. I see following directory structure in `collection-root`: <img width="433" height="326" alt="Image" src="https://github.com/user-attachments/assets/c20ed268-a18b-43ba-8bd6-7d5265e04231" /> My `/config` directory contains default `config` file and `users` file with 2 users and their bcrypt hashes. Can these existing directories be explained by anything other than my instance somehow becoming compromised? I am not aware of the app having any open endpoints not requiring authentication from the `users` file. I'm really confused by this.