Unfortunately, it happens to mine (iPad2) after each time I do reset. I have to redo the "turn off Passcode lock; reset iPad; turn on iPad and turn on Passcode lock" (see above).
Sorry, JCTC. I don't know any other way around this. Also having trouble with posting on forums like this -- it sometimes freezes in the middle of a post.
I did read at the other thread that it may be something to do with a 4 number Passcode. The person changed to a longer Passcode and I believe the problem stopped for them. I have not tried that.