I created a virtual machine with this command

./pre-inst-env guix system vm ~/configs/vm-config-desktop.scm \
   --image-size=10GB \
   --expose=$HOME \
   --share=$HOME/tmp=/exchange

I run this virtual machine with this command

/gnu/store/zlnjsjgw8d0b6p1p7c3dbh4g6x80mrq6-run-vm.sh

Sometimes the graphical login screen comes up

Sometimes it doesn't and a login form in a terminal gets proposed

This happens randomly