Hopefully, you've solved this problem already. When I experienced it on an HPUX system about 5 years ago, everyone went hunting for a Pro/e option or parameter that could account for it. Turned out, as well as I can remember, it was a system issue, something with a type-ahead buffer not being large enough so that when you typed fast and it didn't have a letter in the buffer, it duplicated the last one in the buffer. The reason Pro/e had this problem and not other applications is that Pro/e seemed to be the only one that read from that buffer, a holdover from the days of very slow dumb terminals or at least very slow displays, the kind where you'd stop typing and watch the last 2-3 letters print on the screen. Anyway, the solution turned out to be just increasing the size of this buffer. Don't remember if the sysadmin had to do it or if it was a local workstation setting.
David Janes