audit: type=1400 audit(1642063521.864:246): apparmor="DENIED" operation="ptrace" profile="snap.firefox.firefox" pid=9868 comm="Shutdow~minator" requested_mask="trace" denied_mask="trace" peer="snap.firefox.firefox"
I really don't like it, but turning off Apparmor worked for me. Not sure what caused AppArmor to start complaining all of a sudden.