This problem has been verified on a Lenovo W700 and a Lenovo P17 on both Sketchup 2017 and the most current version. The problem can be easily reproduced by opening a new drawing and creating a cube. Try selecting any surface then push or pull it. Move the cursor to another surface on the cube and press the space bar to change the cursor context. Then press the left Trackpoint button. The surface should be selected but 80% of the time it is not and you must press the Trackpoint button a second time to select the surface. Move the cursor to another face of the cube, press the space bar then the left Trackpoint button and there is a 20% chance that it will work the first time. This problem occurs if you use the Trackpoint button or touch the touch pad. The problem does not occur if you use a real mouse or push down on the left bottom corner of the touchpad.
I also tested the Web version after changing navigation to the touchpad, same problem.
The P17 and W700 are both maxed out configurations. I suspect that this problem is reproducible on all Thinkpads.
If you can’t reproduce the problem, contact me and I will walk you through the steps to re-create the problem.