This problem is solved. I can't reproduce it anymore using
$ guix describe
Generation 64 Mar 20 2020 13:54:14 (current)
guix 830dab8
repository URL: https://git.savannah.gnu.org/git/guix.git
branch: master
commit: 830dab870ab1d4a4ec1127a877a43d19f86c4f7f$ yelp --version yelp 3.32.2
