Initrd build Error: failed to copy "/nix/store/.../systemd" to "./root/nix/store/.../systemd"

The error: $ sudo nixos-rebuild --impure --flake .#$HOSTNAME switch --show-trace building the system configuration... error: Cannot build '/nix/store/c193hazsr5da4vz4zm2k2nqm46w5zkli-initrd-linux-6.18.49.drv'. Reason: builder failed with exit code 1. Output paths: /nix/store/zdbc3m1cg54v5jc8wg0jxnaf2y32r88n-initrd-linux-6.18.49 ... full log redacted, see pastebin link below > Error: failed to copy "/nix/store/sm8d6jpilwdy3bw3yq2lv8rr8jld26pb-systemd-26...