I had no problem on my XPS 13 9360, *until* I upgraded the BIOS to 2.10.0.
Since upgrading, I have the problem on external USB keyboard, if connected through the WD15 docking station. USB-C.
The external keyboard seems ok if connected directly to the laptops USB.
I'm also having the same issue re my brand new Dell XPS is failing to register all my key strokes - absolutely frustrating!
I've tried some of the fixes but still not fixed - have Dell released a fix as yet?
Or have they even confirmed there is a problem?