Oddly, downloading
<https://ci.guix.gnu.org/nar/lzip/hrdzapsn1sxsybl1x2yfjj31lp84wi4s-libreoffice-6.4.7.2>
with the browser (IceCat) or `guix download` works just fine
(fast and 100% completion).

To reproduce:
guix time-machine --commit=23a5dcce1d893b8f5c5301ae3c1af863776ed3cf \
  build libreoffice

Some other packages seem to be affected as well, but I don't recall
exactly which.

Maxime