XPS 13 keyboard doesn't detect simulataneous keypresses reliably (all models)

I've got a problem with all XPS 13 models I've tested, and that's the 9350 (which I own), the 2017 model and the brand new 9370 model.

When I press multiple keys at exactly the same time, in about 10-20% of cases only one of the two keypresses is detected. Simple test: open a text editor and try to press keys A and S at the same time. Watch closely what appears on screen. Most of the time, you'll see "as" or "sa". But sometimes you'll see only "a" or "s".

You might ask: why is this important for the XPS 13 (it is no gaming machine). The problem is it can be any two keys, including modifier keys. In my case, as a power user I often use keyboard shortcuts with two modifier keys, such as Ctrl-Shift-F for formatting code in my IDE. My 30+ years of muscle memory is trained to press all modifier keys at the same time, then press the non-modifier key. On the XPS 13, this often leads to uppercase F letters (Shift-F) inserted into my source code or another shortcut being invoked (Ctrl-F = Find).

The issue is independent of the operating system. I tested the preinstalled Windows, the preinstalled Ubuntu (on the developer edition), and updated Ubuntu (16.04) and I think also keyboard input in the BIOS itself. The XPS 15 line doesn't seem to exhibit this problem, at least I could not reproduce the problem on a 2016-ish XPS 15.

So Dell, pretty please, can you fix this keyboard issue and hopefully release the fix as a BIOS upgrade also for the older models? Most likely, you had it already fixed at some point on the XPS 15.