It looks like this was their plan all along and it's the reason why they are not sending us the replacement mounts yet. Here's my theory:
They were originally using the full circle mounts which were great. You can see in
KiDyNomiTe's review (4th and 6th pictures) that the mount has the full circle. Then somewhere along the line, they decided to change to the 2/3 circle (reducing the materials = cheaper and/or lighter?).
Then it turns out that the 2/3 circle mounts have seized ball joints. I'm guessing they don't have S13s/S14s at their disposal for testing so they are sending out some full circle and some 2/3 circle mounts as replacements. They're probably going to hear that the full circles fixed the problem and the 2/3 circles still have the problem.
Well, that's my theory anyway.