Quality control in China is very bad.
I buy a product out of China and i was going to change factories but when talking to the new factory there were too many red lights and they couldn't be trusted. My agents just wouldn't go there they get burnt a fair bit by factories and say if you find a good one stick with it. I would say 15% are trustworthy.
BTW there is some very good shit, my product is on par with the best in the world and at a cheap price, and i will start putting it into America early next year. But there are a lot of fuck-ups i'd hate to have to eat something from there