Running Authelia in a container makes my configuration directory immutable. How and why?

Trying to learn full stack website development. I've a sample project I've spun up that uses Authelia for authorization. Authelia is running in a docker container. My server is running Debian Trixie. Everything is working fine, except, somehow after I spin up the Authelia container my Authelia configuration directory and all files in it are immutable. The directory in question is a read-write bind mount of a local directory onto /config in the Authelia container.

lsattr denies that the directory is immutable, but I can no longer write to it or modify any files in it. This problem persists after the Authelia container is stopped, and even after a reboot that does not restart Authelia.

This is annoying because I am often changing the config directory as I learn what I am doing. Its not a big deal; I can delete the directory and recreate it, but I am indeed puzzled.