HTC Desire :: Letters Insert By Itself

Probably as many others i decided to move on from i phone platform to android and bought a new Desire 2 days ago and trying to catch up with it. I am generally very impressed with the device except 1 critical issue I'm having: When typing very fast in the keyboard, the keyboard gets lost completely, i am very fast typing person and do a lot of emails I'm text etc. I can see when typing that random letters kick in the text. I did a test by fast typing letters A-L to see exactly and a random latter like G, F being inserted without my interaction while I'm pressing only A and L. This is mostly happening in vertical mode. Landscape is much better Can someone tell me what is going on please? I did calibration many times and no result. I downloaded keyboards from the Market - nothing. I goggled the web for something - nothing there. Has some came across this issue? it is so frustrating and if i don't find solution how to fix it i will have to return it to a shop.