if you type pretty quick i think you go too fast for it to do it. I can type fast enough on this thing that im hitting nearly 3 keys at almost the same time so itd be hard pressed to keep up accuratley.
Mine is the same way...intermittent. I went to the sprint store and the demo phone was too, although unlike mine it always vibrated.. Mine is hit or miss. I can deal with it, however, I just dont want it to be a sign of potential problem or defect... Id rather swap early when I can get a new Evo rather than wait and and get a refurbed unit..