Incidentally, a third bug comes into play here, it's not possible to easily determine which live object blocks the corrupted files, that is quite annoying as well:
$ guix gc -D /gnu/store/l0hs8cydj71z1l38d79bjzizr2lmarq9-upgrade-shepherd-services.scm.drv finding garbage collector roots... guix gc: erreur : cannot delete path `/gnu/store/l0hs8cydj71z1l38d79bjzizr2lmarq9-upgrade-shepherd-ser ices.scm.drv' since it is still alive zsh: exit 1 guix gc -D $ guix gc --referrers /gnu/store/l0hs8cydj71z1l38d79bjzizr2lmarq9-upgrade-shepherd-services.scm.drv $ guix gc --derivers /gnu/store/l0hs8cydj71z1l38d79bjzizr2lmarq9-upgrade-shepherd-services.scm.drv -- Best regards, Nicolas Graves