Rebasing other users' MRs for packages

Not sure if this is intentional but trying to rebase the branch in this MR is giving me a "something went wrong": https://gitlab.archlinux.org/archlinux/packaging/packages/sway/-/merge_reque... I would guess that the person just didn't check the "let the maintainer edit the commits" or something but I'd expect a less generic error message. Is this intentional behavior or broken behavior?