/usr/bin/update-manager:apt_pkg.CacheMismatchError:foreach_cb:<listcomp>:packages_are_selected:is_selected:marked_delete

[errors.ubuntu.com bug bridge]

[Impact]

 * Update-manager crashes when it tries to remove a package not existing in the archive that was already removed since update-manager refreshed its cache.
 * The fix TODO

[Test Case ]

 (with Bionic's package names)
 * Install older kernel packages, downgrade a few packages and mark the kernels autoremovable:
   $ wget http://mirrors.kernel.org/ubuntu/pool/main/l/linux-hwe/linux-headers-4.8.0-36_4.8.0-36.36~16.04.1_all.deb
   $ sudo dpkg -i linux-headers-4.8.0-36_4.8.0-36.36~16.04.1_all.deb && sudo apt-mark auto linux-headers-4.8.0-36 && sudo /etc/kernel/postinst.d/apt-auto-removal
   $ sudo eatmydata apt install -y --allow-downgrades libpoppler73=0.62.0-2ubuntu2 poppler-utils=0.62.0-2ubuntu2

 * Start update-manager in a different terminal and _don't_ start the upgrade

 * Remove kernel packages behind u-m's back:
   $ sudo apt purge -y linux-headers-4.8.0-36

 * Click Settings.. on update-manager's GUI, then Close on the appearing dialogue. In buggy versions a crash with apt_pkg.CacheMismatchError is shown in the terminal, in

[Regression Potential]

 * TODO

[Original bug text]

The Ubuntu Error Tracker has been receiving reports about a problem regarding update-manager. This problem was most recently seen with package version 1:18.10.7, the problem page at https://errors.ubuntu.com/problem/e5025f8bd160fe34610030a2f4386a39418f0271 contains more details, including versions of packages affected, stacktrace or traceback, and individual crash reports.
If you do not have access to the Ubuntu Error Tracker and are a software developer, you can request it at http://forms.canonical.com/reports/.