Nobody should be surprised. Apple has meticulous QA that always prevents faults like this from reaching consumers. This is another reason why I love Apple. They always put product perfection ahead of shipping x number of units to meet initial demand. Yes there may be shortages for the time being, but the assurance you are getting a world class product should make those delays more palatable.
Not sure if that is sarcasm... Apple has been notorious for Rev A hardware troubles. Mac mini graphics issues, iMac motherboard problems, Macbook Pro retina display issues, Macbook Pro 2009 SATA interface issues...
That said, if the watch has some benefit to you, this is a palatable story regarding delay. They are taking the time to try and ensure they get this one right.