After wrestling with this issue some more and trying to figure out the cause, I finally fingered Ubuntu as the culprit.
Something in my upgrade from Ubuntu 18.04 LTS to Ubuntu 20.04 LTS subtly broke my system. Also I think a recent change in guix preventing me from doing a 'guix pull' unless logged in as root might have had something to do with it.
) to help anyone else experiencing the issue.