Seat belt lock-up is found on other Nissan's as well. My 02 Altima has this problem, which I have had checked and re-checked by the dealer, yet they couldn't replicate the problem. So one day, I happened to get into a rear passenger seat, and disovered two actions that seem to prompt the problem:
a. quickly pulling the seat belt out almost to its limit
b. quickly pulling the seat belt out and upward rather than out and downward.
Either action employs the ratchet locking mechanism. I also realize that it only happens in passenger seats, and not in the driver's seat. So the next time I was at the dealer for scheduled maintenance, I mentioned it and the service manager checked through some service manuals for me. It turns out that this is apparently part of the constuction of the belt recoil mechanism by design.
So - now we pull out the belts out in a slower, outward and slightly downward motion, and we avoid the lockup altogether.
My guess is that Nissan uses the same belt recoil mechanisms in all it's vehicles, but may be implemented slightly differently so as to accentuate or eliminate the problem in various models.