Touchpad mouse keys are not detected from time to time - how to analyse and solve this for Lenovo T14 Gen2 in Ubuntu 22.04.4 LTS?

My Lenovo T14s Gen2 laptop has a touch-pad with three mouse keys above it (left | middle | right mouse key).

Since approximately two weeks, I have the issue, that - perhaps for ten minutes - these three mouse keys do not work. So I can press them but the action is not executed.

E.g. Rebooting, suspending and returning all do not change this.

What does help: just wait for (perhaps) 10 minutes. Then those keys will work again.

After suspending this issue might come up again.

Where (e. g. in which log file) could I analyze for the root cause?

If somebody already knows it: what is the root cause and how can I repair it permanently?

PS: workaround is presently to use the touch-pad itself to execute left and right mouse clicks.

More details:

lsb_release -aNo LSB modules are available.Distributor ID: UbuntuDescription:    Ubuntu 22.04.4 LTSRelease:    22.04Codename:   jammywmctrl -mName: CompizClass: N/APID: N/AWindow manager's "showing the desktop" mode: OFFprintf 'Desktop: %s\nSession: %s\n'"$XDG_CURRENT_DESKTOP" "$GDMSESSION"Desktop: Unity:Unity7:ubuntuSession: unity

UPDATE:

when pressing / releasing one of the three buttons, in /var/log/sylog and /var/log/kern.logI can see the following entries:

... computer kernel: [ ...] psmouse serio1: Touchpad at isa0060/serio1/input0 lost sync at byte 6

Sometimes the following entries are created:

... computer kernel: [ ...] psmouse serio1: issuing reconnect request

... computer kernel: [ ...] psmouse serio1: Touchpad at isa0060/serio1/input0 - driver resynced.

None of these entries does "cure" the behaviour.