After some time the Synaptics touchpad stops working, probably triggered by a gesture but I can't say exactly. Sometimes the touchpad is not even recognized as such but only as generic PS/2 mouse.
I will attach the files requested by https://wiki.ubuntu.com/DebuggingTouchpadDetection
ProblemType: Bug
DistroRelease: Ubuntu 21.04
Package: xserver-xorg-input-libinput 0.30.0-1ubuntu1
ProcVersionSignature: Ubuntu 5.11.0-25.27-generic 5.11.22
Uname: Linux 5.11.0-25-generic x86_64
ApportVersion: 2.20.11-0ubuntu65.1
Architecture: amd64
BootLog: Error: [Errno 13] Keine Berechtigung: '/var/log/boot.log'
CasperMD5CheckResult: pass
CurrentDesktop: ubuntu:GNOME
Date: Mon Aug 16 10:57:28 2021
DistUpgraded: Fresh install
DistroCodename: hirsute
DistroVariant: ubuntu
InstallationDate: Installed on 2021-08-14 (1 days ago)
InstallationMedia: Ubuntu 21.04 "Hirsute Hippo" - Release amd64 (20210420)
MachineType: LENOVO 20CLS03Y00
ProcEnviron:
TERM=xterm-256color
PATH=(custom, no user)
XDG_RUNTIME_DIR=<set>
LANG=de_DE.UTF-8
SHELL=/bin/bash
ProcKernelCmdLine: BOOT_IMAGE=/boot/vmlinuz-5.11.0-25-generic root=UUID=31684594-5368-496c-9212-f7a83f630717 ro quiet splash vt.handoff=7
SourcePackage: xserver-xorg-input-libinput
UpgradeStatus: No upgrade log present (probably fresh install)
dmi.bios.date: 04/08/2021
dmi.bios.release: 1.41
dmi.bios.vendor: LENOVO
dmi.bios.version: N10ET62W (1.41 )
dmi.board.asset.tag: Not Available
dmi.board.name: 20CLS03Y00
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.ec.firmware.release: 1.16
dmi.modalias: dmi:bvnLENOVO:bvrN10ET62W(1.41):bd04/08/2021:br1.41:efr1.16:svnLENOVO:pn20CLS03Y00:pvrThinkPadX250:rvnLENOVO:rn20CLS03Y00:rvrNotDefined:cvnLENOVO:ct10:cvrNone:
dmi.product.family: ThinkPad X250
dmi.product.name: 20CLS03Y00
dmi.product.sku: LENOVO_MT_20CL_BU_Think_FM_ThinkPad X250
dmi.product.version: ThinkPad X250
dmi.sys.vendor: LENOVO
version.compiz: compiz N/A
version.libdrm2: libdrm2 2.4.105-3~21.04.1
version.libgl1-mesa-dri: libgl1-mesa-dri 21.0.3-0ubuntu0.2
version.libgl1-mesa-glx: libgl1-mesa-glx N/A
version.xserver-xorg-core: xserver-xorg-core 2:1.20.11-1ubuntu1.1
version.xserver-xorg-input-evdev: xserver-xorg-input-evdev N/A
version.xserver-xorg-video-ati: xserver-xorg-video-ati 1:19.1.0-2
version.xserver-xorg-video-intel: xserver-xorg-video-intel 2:2.99.917+git20200714-1ubuntu1
version.xserver-xorg-video-nouveau: xserver-xorg-video-nouveau 1:1.0.17-1
Same problem with touchpad in Windows 10 with all the latest Lenovo drivers, so it might be a hardware defect. Sent it back for a refund.