The company needs to overcome these hurdles to keep its growth machine spinning.PDD Holdings (PDD 0.65%) has been the best-performing Chinese tech company in the last 12 months -- until lately. Despite reporting solid quarterly earnings, stock in Pinduoduo's parent company plunged by more than 30% as investors sold it amid the company's pessimistic guidance on its prospects.Still, contrarian investors and PDD Holdings bulls are taking this sell-off to buy the stock on the cheap. But before they rush into lo ...