Although it might not affect all Dell XPS 15 9575 units that were patched with the latest BIOS update, it seems that at least some of this convertible's users are now facing a buggy trackpad. For now, the problem is being investigated by Dell's engineers, so a solution should surface as soon as possible.
https://www.notebookcheck.net/Latest-Dell-XPS-15-9575-BIOS-update-comes-with-a-trackpad-bug.321180.0.html
The trackpad issue is still present. I have Dell XPS 15 9575. The problem started after a BIOS update and still persists (with all drivers and newest BIOS in place). Have no idea if this is on Dell's radar or if this is even a large enough issue across users for this device. Seen a few posts on various forums describing the same thing your article talks about, but no solutions.