updating package does a hard shutdown

[Alex]

I have a Eaton 3S 550 UPS connected via USB to my Linux machine. On a default install of Ubuntu 16.04 the UPS is not properly recognized and shows as empty in the power menu. The system does not shut down as the action to "When power is critically empty" in the power configuration panel is by default set to nothing.

Upgrading the package causes a notification to pop up, stating that the power is critically low and the system will shut down shortly. The system then shuts down despite the upgrade of other packages still being in progress.
Upon restart the forced shutdown does not reoccur.

I wish to stress that this bug is not filed against this specific model of UPS not being properly recognized on a clean install, but instead that during upgrade the default action for critically low power seems to change for a short period, causing the shutdown of the computer

ProblemType: Bug
DistroRelease: Ubuntu 16.04
Package: upower 0.99.4-2ubuntu0.2
ProcVersionSignature: Ubuntu 4.4.0-28.47-generic 4.4.13
Uname: Linux 4.4.0-28-generic x86_64
ApportVersion: 2.20.1-0ubuntu2
Architecture: amd64
Date: Fri Jul 1 12:20:03 2016
ExecutablePath: /usr/lib/upower/upowerd
InstallationDate: Installed on 2016-07-01 (0 days ago)
InstallationMedia: Ubuntu 16.04 LTS "Xenial Xerus" - Release amd64 (20160420.1)
SourcePackage: upower
UpgradeStatus: No upgrade log present (probably fresh install)