I was hoping it was a transient issue but now not so sure...

DEBUG util.py:490:  BUILDSTDERR: Unable to detect release version (use '--releasever' to specify release version)
DEBUG util.py:490:  BUILDSTDERR: Failed to synchronize cache for repo 'build', disabling.
DEBUG util.py:490:  BUILDSTDERR: Warning: Module or Group 'build' does not exist.
DEBUG util.py:490:  BUILDSTDERR: Error: Nothing to do.

Thanks,
Richard