I'm happy to accept any of the stems that have an issue for inspection, and happy to send you a prepaid label for that purpose. I'm extremely curious about what is going on. Can you send some pics of the steerer tube portion of the headset as well? Do you have digital calipers available? What sort of steerer tube is the Ritchey stem working on? Aluminum, steel, carbon, standard threadless adapter?

The only time I've ever had a questionable stem to steerer clamping arrangement was a Ritchey WCS stem on LOOK (circa 2004) carbon steerer. Like most carbon steerers, the finish is as smooth as glass but the main issue is that the steerer tube was undersized so the pinch clamp on the stem was bottoming out at (or near) full torque. That same stem clamps solidly on an innicycle steerer, though.

I mention all this not to try to prove anyone wrong, just to add to the conversation. Weird stuff happens and I've learned several times that the hardest part of designing stuff like this is accommodating the parts for which I have no control (fork steerer tubes and stems in this case).