On the Lenovo Yoga series it is necessary to not only disable the touchpad (#102408) but also the trackpoint and keyboard (on the X1 Yoga the keyboard hardware disables, but apparently this does not happen on the consumer Yoga products).
See also https://bugs.freedesktop.org/show_bug.cgi?id=102408#c8
branch for testing: https://github.com/whot/libinput/tree/wip/disable-keyboard-in-tablet-mode
I can confirm that the branch turns off the trackpoint (cannot test keyboard as that gets hardware disabled at the same time).
Author: Peter Hutterer <firstname.lastname@example.org>
Date: Wed Sep 20 14:40:59 2017 +1000
fallback: suspend internal keyboards and trackpoints on tablet-mode switch