I tested downgrading and updating linux and headers between arch1-2 and arch1-1.
It occur only for updating.
kernel ver using to boot is not related.
uname -a
(2/3) Remove DKMS modules
==> dkms remove --no-depmod -m broadcom-wl -v 6.30.223.271 -k 5.11.8-arch1-1
rmdir: failed to remove '': No such file or directory
occurs when updating kernel package.
and unneeded directory remain at /usr/lib/modules/VERSIONOFOLDKERNEL .
It does not happen with ntfs3-dkms in other PC.
Edit:It seems solved by reinstalling every *-dkms package.
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