i have faced gw in kvm fresh installing freezing , whonix 11. and i think i know how to reproduce it.
after installing the gw and the ws (by just making them appeared inside the kvm) , open the gw and keep it open till it finish the installation then make apt-get update and apt-get upgrade. (all that without opening the ws)
now open the ws then wait till it finish. then make sudo apt-get update, then go to the gw = nothing is moving and it cant be shutdown except by "force shutdown".
it is not persistent tho , after the shutdown both of them. they gonna start after that working normally.