09-22-2018 10:31 AM
I was able to reproduce this problem.
I then installed https://ftp.hp.com/pub/softpaq/sp91501-92000/sp91849.exe. (From https://support.hp.com/us-en/product/detect, Software and Drivers, Driver-Keyboard, Mouse and Input Deices, HP Pointing Device Driver, 220.127.116.11 Rev.A 2018-09-07.) The Synaptics Pointing Device driver was then updated from 18.104.22.168, 2018-01-25 to 22.214.171.124, 2018-08-15 (after a restart). Then I was unable to reprocduce the problem.
I also tried to uninstall the Synaptics Pointing Device in the device manager, and it was replaced with PS/2 Compatible Mouse, Microsoft, 10.0.16299.15, 2006-06-21 (after a restart). Then I also was unable to reprocduce the problem.
11-07-2018 10:16 AM
Having the same problem on a brand-new HP 840 G5. Track pad works find but not so with the pointing-stick. Cursor regularly jumps around, left-clicks on it's own, and sometime reverts back to prior page.
Very annoying, and clearly a common problem with the 800 series notebooks.