Battery reported as "discharging" when 100% charged although on AC power

[Byte Commander]

I'm on an Acer Aspire E5-773G which is currently connected to AC power and has its battery fully charged.

Nevertheless, `upower` reports the battery status as "discharging" and also the standard Unity power indicator shows the normal full-battery icon (not charging) and a percentage of 100%.

ANd what is even more strange is that the battery's "energy-full" value suddenly is bigger than "energy-full-design" although it used to slowly decrease during the last months and was a few percent below last time I checked.

This is the `upower --dump` output:

Device: /org/freedesktop/UPower/devices/line_power_ADP1
  native-path: ADP1
  power supply: yes
  updated: Mi 03 Aug 2016 13:04:03 CEST (14551 seconds ago)
  has history: no
  has statistics: no
  line-power
    warning-level: none
    online: yes
    icon-name: 'ac-adapter-symbolic'

Device: /org/freedesktop/UPower/devices/battery_BAT0
  native-path: BAT0
  vendor: SANYO
  model: AL15A32
  serial: 41547
  power supply: yes
  updated: Mi 03 Aug 2016 17:06:34 CEST (0 seconds ago)
  has history: yes
  has statistics: yes
  battery
    present: yes
    rechargeable: yes
    state: discharging
    warning-level: none
    energy: 34,9872 Wh
    energy-empty: 0 Wh
    energy-full: 37,0444 Wh
    energy-full-design: 37 Wh
    energy-rate: 10,3452 W
    voltage: 17,321 V
    time to empty: 3,4 hours
    percentage: 100%
    capacity: 100%
    technology: lithium-ion
    icon-name: 'battery-full-symbolic'

Device: /org/freedesktop/UPower/devices/DisplayDevice
  power supply: yes
  updated: Mi 03 Aug 2016 17:02:03 CEST (271 seconds ago)
  has history: no
  has statistics: no
  battery
    present: yes
    state: discharging
    warning-level: none
    energy: 34,9872 Wh
    energy-full: 37,0444 Wh
    energy-rate: 10,3452 W
    time to empty: 3,4 hours
    percentage: 100%
    icon-name: 'battery-full-symbolic'

Daemon:
  daemon-version: 0.99.4
  on-battery: no
  lid-is-closed: no
  lid-is-present: yes
  critical-action: PowerOff

ProblemType: Bug
DistroRelease: Ubuntu 16.04
Package: upower 0.99.4-2ubuntu0.3
ProcVersionSignature: Ubuntu 4.4.0-31.50-generic 4.4.13
Uname: Linux 4.4.0-31-generic x86_64
NonfreeKernelModules: nvidia_uvm nvidia_drm nvidia_modeset nvidia
ApportVersion: 2.20.1-0ubuntu2.1
Architecture: amd64
CurrentDesktop: Unity
Date: Wed Aug 3 17:35:20 2016
InstallationDate: Installed on 2016-05-04 (90 days ago)
InstallationMedia: Ubuntu 16.04 LTS "Xenial Xerus" - Release amd64 (20160420.1)
SourcePackage: upower
UpgradeStatus: No upgrade log present (probably fresh install)