The error message looks like this:
snap-confine has elevated permissions and is not confined but should
be. Refusing to continue to avoid permission escalation attacks
It's due to Apparmor and the kernel you're running. I remedied this with:
# apparmor_parser -r /etc/apparmor.d/*snap-confine*
# apparmor_parser -r /var/lib/snapd/apparmor/profiles/snap*