it’s very common,reported years ago(yet not fixed),apparently cosmetic and nothing to worry about.
“the Arch-dev says that the shutdown hook is a deprecated method and shouldn’t be used”.
https://lists.archlinux.org/pipermail/arch-dev-public/2013-December/025742.html
it happens to me too most of the time when shutting down.
i do think it’s related to my intel nvidia laptop and which one i choose to run .
https://bbs.archlinux.org/viewtopic.php?id=233820
https://bbs.archlinux.org/viewtopic.php?id=234329