Additionally, we can see in the unattended-upgrades.log file that unattended-upgrades will be upgraded. Please run the test again with unattended-upgrades version 0.90ubuntu0.5 on a xenial system. My testing has indicated that there may have been an issue with installing updates and shutting down but this should be resolved with the version of the package in -updates.
The description of the bug contains the following:
$ apt-cache policy unattended-upgrades upgrades:
unattended-
Installed: 0.90
Candidate: 0.90ubuntu0.5
Additionally, we can see in the unattended- upgrades. log file that unattended-upgrades will be upgraded. Please run the test again with unattended-upgrades version 0.90ubuntu0.5 on a xenial system. My testing has indicated that there may have been an issue with installing updates and shutting down but this should be resolved with the version of the package in -updates.