Encountered same problem again on both machines (recently installed guix on laptop and an old desktop PC of mine).
Seems like the problems arise after home reconfiguration. Still can pull successfully from the root user.
On "usual user" I have to move all my stuff from home to a separate directory.
cd ~; mkdir vault; mv * vault; mv .* vault;
Then
guix pull works. Of course all the home configuration content is lost.
And I have to reconfigure my home. And then recover all files except
for ".guix-home" and etc. from the "vault" dir.
I wondered that happens because of wrong lang/locale settings, So I even forced them in my user's config:
(simple-service 'some-useful-env-vars-service
home-environment-variables-service-type
`(("LC_ALL" . "en_US.UTF-8")
("LANG" . "en_US.UTF-8")
("GDM_LANG" . "en_US.UTF-8")
("LANGUAGE" . "en_US")
("EDITOR" . "emacs")))
Still the same problem.