can not open jammy-backports

[Tim Wood]

Software updater asked that I "report this bug". Full message:

"An unresolvable problem occurred while initializing the package information.

Please report this bug against the 'update-manager' package and include the following error message:
E:can not open /var/lib/apt/lists/archive.ubuntu.com_ubuntu_dists_jammy-backports_InRelease - fopen (13: Permission denied), E:The package lists or status file could not be parsed or opened."

Further information:

the file in question is owned by _apt with perms 600. All others in directory are owned by root with 644 perms:
-rw------- 1 _apt root 107692 May 29 06:26 /var/lib/apt/lists/archive.ubuntu.com_ubuntu_dists_jammy-backports_InRelease

"_apt" as a usernmae does not show up with sudo grep -r on /var/log/* (other than the grep command itself)

Action taken:
changed ownership and permission on file to match other files

ProblemType: Bug
DistroRelease: Ubuntu 22.04
Package: update-manager 1:22.04.10
ProcVersionSignature: Ubuntu 5.19.0-41.42~22.04.1-generic 5.19.17
Uname: Linux 5.19.0-41-generic x86_64
ApportVersion: 2.20.11-0ubuntu82.5
Architecture: amd64
CasperMD5CheckResult: unknown
CurrentDesktop: ubuntu:GNOME
Date: Mon May 29 11:19:01 2023
InstallationDate: Installed on 2020-05-12 (1111 days ago)
InstallationMedia: Ubuntu 20.04 LTS "Focal Fossa" - Release amd64 (20200423)
PackageArchitecture: all
ProcEnviron:
 PATH=(custom, no user)
 XDG_RUNTIME_DIR=<set>
 LANG=en_US.UTF-8
 SHELL=/bin/bash
RebootRequiredPkgs: Error: path contained symlinks.
SourcePackage: update-manager
UpgradeStatus: No upgrade log present (probably fresh install)

[Julian Andres Klode (juliank)]

Reassigning and marking incomplete as we can't act on that if we don't have a reproducer or know why it happened to not chown() when it moved the file out of partial/

[Launchpad Janitor (janitor)]

[Expired for apt (Ubuntu) because there has been no activity for 60 days.]