I noticed this in the log:

Failure with UpdatePackages of: Error while installing package: unable to make backup link of '/.etc/apt/sources.list.d/cros.list' before installing new version

This can be reproduced by using the default container and then doing a 'sudo apt-get update && sudo apt-get install cros-apt-config' and the failure will come when installing cros-apt-config.

This is likely due to how we changed the way the repo URLs work for our managed packages.