My guess, you got a bad chain, or the factory did not properly lube the inside of the chain. Keep in mind that not all parts off of the same assembly line are equal. Sometimes materials will have weak spots in them. Maybe the lubing machine ran out of lube in the middle of assembling a chain and missed several links, if not the whole chain.

This same thing happens with every thing that is mass produced, there is no way to ensure 100% quality control, most companies aim for less than 2-3% failure/rejects and that is acceptable. Every once in a while something that is not up to snuff makes it into the market.