If you unpack guix-binary-0.8.2.x86_64-linux.tar.xz according to the manual instructions in "Binary installation", you clobber the ownership of /, /root, and /var.
The tarball needs to unpack with root ownership. While you can use --no-same-owner, the current behaviour is pretty unfriendly. (I noticed because ssh as root then failed with complaints about an insecure .ssh directory.)
