Pinning /usr/bin ran the packaged helper even where the migration came from somewhere else. Under a dev link the migration is read from the checkout while /usr/bin still holds the last installed package, and a package predating __migrate prints its usage and fails the update. By name, the unprivileged call goes through PATH and the sudo call through secure_path, which is how other migrations reach their helpers and which lands on /usr/bin on an install.
Co-Authored-By: Codex XHigh <noreply@openai.com>