Much better than the auto manufacturers.
It is hard to see how their testing didn't reveal a problem.
I do test and dev work for the auto industry, a bug part of my job is pulling apart in house test units, and doing customer FA. I can tell you from experience, it doesn't matter how thoroughly we test a part, or how crazy of a test regime we come up with, a customer will always find a way to break rhe unbreakable, often in new and exotic ways.
While the knee jerk is to say this is a less sturdy design and blame the failures on that, the B model made it through PV, DV, and PPAP. There is a chance this is a supplier issue in one or more of the parts causing the pin failures, and with in spec parts the B model might be just as reliable as the A. Bringing any product or redesign online means teething problems, and sometimes things slip through.
If anything I am pretty impressed that big M is willing to ditch the redesign for the sake of their reputation.