I committed a patch for this in https://github.com/ltsp/ltsp/issues/367.
I'll leave it up to vagrantc to see if he prefers to do a 21.01-2 release + upload,
or an ltsp 22.01-1 backport to bullseye next year right after that release,or we could just tell bullseye+backports ltsp users to get the newest ltsp from the upstream ppa (https://ltsp.org/docs/ppa/).
Thanks!
