#23778 pointed guix time machine to commit fa17abf1af09570708daa28dd40ffbc932ebe25c, which was working initially, but that commit seems to have disappeared upstream generating the following error
Updating channel 'guix' from Git repository at 'https://git.savannah.gnu.org/git/guix.git'...
guix time-machine: error: Git error: object not found - no match for id (fa17abf1af09570708daa28dd40ffbc932ebe25c)