Credhub and conjur credential managers

We have been using credhub as our credential manager for several years without issue.
We are adding conjur as an additional credential manager. credhub holds the ‘platform’ secrets required to integrate with the CI/CD environment and the platforms, while conjur will hold the ‘application’ secrets required to run the deployed applications.

My question(s) is about troubleshooting this dual-credential manager integration.
My credhub credentials are stored in /concourse//{{.secret}} and referenced using ((secret))
My conjur credentials are stored in ENV/GROUP/GROUP_{{.Team}}_D/delegation/consumers/{{.secret}} and referenced using ((conjur.secret))

Is ((conjur.secret)) the correct format? I see nowhere where I can actually name the conjur credential manager in the documentation

How can I troubleshoot the error:
failed to interpolate task config: undefined vars: conjur.pcf-testd2