Trackpoint performs button 2 press

[Nikolas Klug]

release: 18.04
xserver-xorg-input-libinput version: 0.27.1-1

Expected behavior: The trackpoint only moves the pointer and does not perform clicks.

Actual behavior: Whenever I use the trackpoint, a (random) button is pressed, most of the time button 2 (middleclick). The button is only rarely release, it usually stays "pressed".
I then can continue to use the trackpoint with the button(s) pressed, they are not pressed again. Example:

motion a[0]=226 a[1]=855
button press 2
motion a[0]=226 a[1]=857
motion a[0]=226 a[1]=858
...

The button(s) are released again when I actually press a mouse button. When I e.g. press mouse button 1 (leftclick), the following happens:
button press 1
button release 2
button release 1

EDIT: Although I'm using Kubuntu, the same bug appears when I boot Ubuntu. The bug does not appear on Windows.

ProblemType: Bug
DistroRelease: Ubuntu 18.04
Package: xserver-xorg-input-libinput 0.27.1-1
ProcVersionSignature: Ubuntu 4.15.0-22.24-generic 4.15.17
Uname: Linux 4.15.0-22-generic x86_64
ApportVersion: 2.20.9-0ubuntu7
Architecture: amd64
BootLog: Error: [Errno 13] Permission denied: '/var/log/boot.log'
CurrentDesktop: KDE
Date: Sun May 27 15:10:41 2018
DistUpgraded: Fresh install
DistroCodename: bionic
DistroVariant: ubuntu
InstallationDate: Installed on 2018-05-24 (2 days ago)
InstallationMedia: Kubuntu 18.04 LTS "Bionic Beaver" - Release amd64 (20180426)
Lsusb:
 Bus 002 Device 001: ID 1d6b:0003 Linux Foundation 3.0 root hub
 Bus 001 Device 005: ID 058f:9540 Alcor Micro Corp. AU9540 Smartcard Reader
 Bus 001 Device 004: ID 5986:0708 Acer, Inc
 Bus 001 Device 002: ID 138a:0090 Validity Sensors, Inc.
 Bus 001 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub
MachineType: LENOVO 20FXS05500
ProcKernelCmdLine: BOOT_IMAGE=/boot/vmlinuz-4.15.0-22-generic root=UUID=705151cf-8e1d-41bf-9ae8-5669e9ac8d40 ro quiet splash nouveau.runpm=0 vt.handoff=1
SourcePackage: xserver-xorg-input-libinput
UpgradeStatus: No upgrade log present (probably fresh install)
dmi.bios.date: 06/07/2016
dmi.bios.vendor: LENOVO
dmi.bios.version: R07ET67W (2.07 )
dmi.board.asset.tag: Not Available
dmi.board.name: 20FXS05500
dmi.board.vendor: LENOVO
dmi.board.version: Not Defined
dmi.chassis.asset.tag: No Asset Information
dmi.chassis.type: 10
dmi.chassis.vendor: LENOVO
dmi.chassis.version: None
dmi.modalias: dmi:bvnLENOVO:bvrR07ET67W(2.07):bd06/07/2016:svnLENOVO:pn20FXS05500:pvrThinkPadT460p:rvnLENOVO:rn20FXS05500:rvrNotDefined:cvnLENOVO:ct10:cvrNone:
dmi.product.family: ThinkPad T460p
dmi.product.name: 20FXS05500
dmi.product.version: ThinkPad T460p
dmi.sys.vendor: LENOVO
version.compiz: compiz N/A
version.libdrm2: libdrm2 2.4.91-2
version.libgl1-mesa-dri: libgl1-mesa-dri 18.0.0~rc5-1ubuntu1
version.libgl1-mesa-glx: libgl1-mesa-glx 18.0.0~rc5-1ubuntu1
version.xserver-xorg-core: xserver-xorg-core 2:1.19.6-1ubuntu4
version.xserver-xorg-input-evdev: xserver-xorg-input-evdev N/A
version.xserver-xorg-video-ati: xserver-xorg-video-ati 1:18.0.1-1
version.xserver-xorg-video-intel: xserver-xorg-video-intel 2:2.99.917+git20171229-1
version.xserver-xorg-video-nouveau: xserver-xorg-video-nouveau 1:1.0.15-2

[Cameron Holman (cam1170)]

I believe I have the same issue https://bugs.launchpad.net/ubuntu/+source/xserver-xorg-input-libinput/+bug/1820884

[Launchpad Janitor (janitor)]

Status changed to 'Confirmed' because the bug affects multiple users.