As I mentioned earlier, I checked everything - including fitment of the handlepost to the steerer tube and the headset, as well as the hinge. The steerer tube sits nice and flush all the way around; the way it's fastened to the steerer tube and the headset is that a big bolt threads into the top of the steerer tube, sandwiching everything - the fork, the headset, and the handlepost - together via a big brass crush washer, keeping them all in line. If there was anything out of alignment, I would've found out about it; steering the bike wouldn't be possible if any component of the handlebar-to-fork assembly was our of whack, as the headset bearings would be jammed in place.

As for the hinge, I found no issues there - no play, no wear, no cracked welds. Nothing out of the ordinary.

As I said earlier, I doubt that contacting Dahon will get me anywhere. Even if it did, and even if they by some miracle decide to honor some kind of warranty, they'll still ask me to pay for shipping a new frame to Saudi Arabia - the cost of which would be so prohibitive at this point that I might as well buy a new bike - which I already did a few months ago, and ran into a whole new set of issues. See my posts about my new Launch D8 and the en****tification of Dahon.