There is some manual interaction needed to tune the size of the data structures in the ISO that I suspect have been broken by recent updates to Gnome and KDE. I’m sure normal service will be resumed after the other fires (e.g. xz) have been extinguished.
I don’t know whether or not Clear uses the known exploit with xz of a modified ssh for systemd notifications, but just to be safe I just saw that xz was updated to 5.6.1 on 41220 so it might be advisable to grab the iso from the Index of /releases/41210/clear/ or earlier and then update from there.