After `guix pull` I was able to upgrade to gajim 1.3.3 with `guix package -u gajim`.

$ guix describe
Generation 36 Oct 25 2021 17:34:08 (current)
guix b0735c7
repository URL: https://git.savannah.gnu.org/git/guix.git
branch: master
commit: b0735c79b0d1d34117ec36d5dc5f14a3f9392bc1

This issue can be closed.