Shock Loss Producing Loss of Grafts from Previous Hair Transplants?

Does shock loss occur in the grafts that were put into the head on prior occasions?

I have seen this occur on very infrequent occasions in men (probably less than a dozen cases). In each and every case, the older grafts regrew when the new hair transplants came in. So the good news is that it does grow back in 2-6 months, but the bad news is that the shock loss happens at all (risk is under 0.1% by my best guess).