It seems kind of careless to have a software update destroy data (w/o backup) Cockpit gives you an editor to change the MOTD to your hearts content (it's not a fixed width font ) but it got deleted...
(Last update on/before Aug 21, 2026:
asl3-appliance
asl3-appliance-pi
cockpit-wifimanager).
I like having a custom MOTD, give me reminders and hints and tips - for instance: Reminder to use rpi-clone. Which actually saved my bacon in this case because I was able to go to the backup drive and navigate to my latest custom MOTD there and restore it back.
The asl3-appliance package is "opinionated" (as documented) in that it will reset various configuration back to expected items. That's both the value and drawbacks of an appliance package.
If you mark /etc/motd as immutable, it won't get overwritten - i.e. chattr +i /etc/motd.