Cannot update Spack builtin package repo when running container interactively

[plexoos]

When running the eicweb/eic_cuda:25.10-stable container interactively, updating the builtin Spack package repository fails silently, and subsequent package installs break.

Steps to Reproduce

$ docker run --rm -it eicweb/eic_cuda:25.10-stable
(Thu Nov-6 2:37:08pm)-(CPU 2.0%:0:Net 1)-(root:/)-(20K:26)
> spack repo ls
[+] eic        v1.0    /opt/spack-packages/repos/eic-spack
[+] k4         v1.0    /opt/spack-packages/repos/key4hep-spack
[+] builtin    v2.2    /opt/spack-packages/repos/spack_repo/builtin
(Thu Nov-6 2:37:15pm)-(CPU 2.0%:0:Net 1)-(root:/)-(20K:26)
> spack repo update -b develop builtin
(Thu Nov-6 2:37:25pm)-(CPU 2.0%:0:Net 1)-(root:/)-(20K:26)
> spack install plog
==> Error: Cannot install 'plog' because no matching specs are in the current environment. You can add specs to the environment with 'spack add plog', or as part of the install command with 'spack install --add plog'
(ERROR)-(Exit Code 1)-(General error)