Adding shabitica channel makes nix-env stop working

[kyren]

This might be expected, and it's not a big deal because I don't do imperative package management on the server that runs my instance of shabitica, but if I add the shabitica channel like:

nix-channel --add https://headcounter.org/hydra/channel/custom/shabitica/nixos-18.09/shabitica shabitica

and do a nix-channel --update, then calling nix-env -qa as a root user gives:

error: cannot auto-call a function that has an argument without a default value ('config')

This error stops as soon as I remove the shabitica channel.

Is this something that's expected and I just should either not be adding shabitica as a channel or not mixing it with imperative package management?