Error: Missing required environment variable RAILWAY_TOKEN when linking preview environment

Determine if preview environment variables refresh in real time when parent project variables change. Preview environments are created from a copy of the project’s environment variables at the moment a pull request opens, and the documentation does not state whether they track subsequent changes to those variables, leaving the behavior uncertain and potentially causing integration tests to pass in preview but fail in production. Does a change to a non‑production variable in the parent project propagate instantly to an already linked preview environment? If not, what action triggers a refresh of the preview’s variable set? Is a manual rebuild of the preview required to see updates?