I just upgraded to the latest Guix and, while downloading substitutes, I
noticed the progress bar seems to never reach 100%, as shown below. I'm
not sure if this started recently or not.

Downloading https://mirror.hydra.gnu.org/guix/nar/gzip/drm4pj1k5mkb5784i0rkqb0bg2z8lmyw-libabw-0.1.1...
 libabw-0.1.1  346KiB                                                                                                                              585KiB/s 00:00 [############        ]  60.0%

Downloading https://mirror.hydra.gnu.org/guix/nar/gzip/djqkmf30zrlwfprdqhmk4nm92iw8ac53-libe-book-0.1.2...
 libe-book-0.1.2  215KiB                                                                                                                           628KiB/s 00:00 [################### ]  96.6%

Downloading https://mirror.hydra.gnu.org/guix/nar/gzip/qjmg7jjcqvclxia9s9b5mw8whm6lpqbz-liblangtag-0.5.8...
 liblangtag-0.5.8  269KiB                                                                                                                          614KiB/s 00:00 [###############     ]  77.2%

Downloading https://mirror.hydra.gnu.org/guix/nar/gzip/7fz9q215cw3nnihr31zmc372zjl00py8-libvisio-0.1.0...
 libvisio-0.1.0  975KiB                                                                                                                            887KiB/s 00:01 [############        ]  60.7%

Downloading https://mirror.hydra.gnu.org/guix/nar/gzip/544jcd4141xgg72dk5xxbs4zjzvxvvxi-nspr-4.17...
 nspr-4.17  404KiB                                                                                                                                 622KiB/s 00:00 [##########          ]  51.5%