It would just freeze up when there are updates that require big resource usage.
First time it happened right after I’ve installed Whonix 11 and ran the first post-install update, at the step of building the initrd for a newer kernel. Recently it happened again while upgrading virtualbox-guest-dkms at depmod stage.
https://www.whonix.org/wiki/FAQ#Graphical_Whonix-Gateway.3F still suggests 128MB RAM minimum, perhaps it should be changed to 192MB RAM? When I’ve increased RAM to that value for Whonix 11 Gateway, the upgrade succeeded.