In the update that I did today Icecat is no longer Deterministic.I compiled Icecat since there doesn't seem to be any substitutes. After the second time it wrote an error that the two builds were not the same.
My system is this:
Generation 13 Jun 25 2020 16:46:39 (current) guix d1a26be repository URL: <https://git.savannah.gnu.org/git/guix.git> branch: master commit: d1a26bedcc63362609604ec36c7a5ebee825d140 Marinus