Rivian Automotive (RIVN 8.25%) has been an extremely volatile stock since its initial public offering in 2021. Yet volatility can often create incredible buying opportunities. After a recent correction, Rivian stock is now too cheap to ignore. And there's one major reason to buy before the end of the month. Let's dive in, and I'll explain.Rivian says it's about to achieve this major milestoneThe electric vehicle (EV) maker has had a lot of success since launching its first two luxury models: the R1T and R1S ...