Quantized Keyboards?

I have before me a Logitech K120, purchased recently because the alt key of the last keyboard gave up and handed in its resignation.

I just seemed to notice something peculiar. And annoying, if true: the keypresses seem to be 'quantized'[1]! Noticed this oddity after something between the spelling center of my brain and the text editor repeatedly failed to spell "Gui". It instead preferred "Giu".

First I suspected that somehow the typing style I use made the I key get depressed before the U key. But after some experimentation, I found the following repeatable behavior: "ui", and "mn", when hit together, for instance by effectively creating a very wide finger out of two of your ten favorite little servants, always produce "iu" and "mn", instead of a mix of both! And there are probably other 'inversion-prone' pairs, but I am just not that interested...

Maybe there is a probe pulse frequency of perhaps 100Hz? Or perhaps it's something in how the keyboard decides to send the detected keys over the USB cable. Well, at least now I know: keyboards aren't created equal. This was a pretty cheap one, though it feels pretty solid.

Maybe I should try to learn a more disciplined, proper touch typing, instead of the 70% touch, 40% two-or-three-key harpeggios, and 10% backspace+retype I use now.

[1] http://en.wikipedia.org/wiki/Quantization_(music)