This seems to be a bug in command-not-found, Python, or any of the libraries it used. For further investigation, we need a core dump from that process, did apport not prompt you for that?
** Package changed: apt (Ubuntu) => command-not-found (Ubuntu) ** Changed in: command-not-found (Ubuntu) Status: New => Incomplete -- You received this bug notification because you are a member of Ubuntu Touch seeded packages, which is subscribed to apt in Ubuntu. https://bugs.launchpad.net/bugs/1940503 Title: Illegal instruction (core dumped) on apt update Status in command-not-found package in Ubuntu: Incomplete Bug description: Ran `apt update` and received Illegal instruction (core dumped) Reading package lists... Done E: Problem executing scripts APT::Update::Post-Invoke-Success 'if /usr/bin/test -w /var/lib/command-not-found/ -a -e /usr/lib/cnf-update-db; then /usr/lib/cnf-update-db > /dev/null; fi' E: Sub-process returned an error code at the end. Ran `apt update` again with no problems. ProblemType: Bug DistroRelease: Ubuntu 20.04 Package: apt 2.0.6 ProcVersionSignature: Ubuntu 5.13.0-1010.11-oem 5.13.1 Uname: Linux 5.13.0-1010-oem x86_64 ApportVersion: 2.20.11-0ubuntu27.18 Architecture: amd64 CasperMD5CheckResult: skip CurrentDesktop: XFCE Date: Thu Aug 19 08:46:31 2021 InstallationDate: Installed on 2018-11-21 (1001 days ago) InstallationMedia: Xubuntu 18.10 "Cosmic Cuttlefish" - Release amd64 (20181017.2) SourcePackage: apt UpgradeStatus: Upgraded to focal on 2020-04-21 (484 days ago) To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/command-not-found/+bug/1940503/+subscriptions -- Mailing list: https://launchpad.net/~touch-packages Post to : touch-packages@lists.launchpad.net Unsubscribe : https://launchpad.net/~touch-packages More help : https://help.launchpad.net/ListHelp