BYD's "gravy train" might be grinding to a halt. The Chinese EV giant's share price slumped as much as 8% on Monday, as investors digested disappointing earnings released last week.On Friday, BYD reported that net profits in the second quarter had fallen 30% from a year earlier, as the Tesla rival grappled with fierce competition in China's congested EV market. BYD has also found itself in the crosshairs of China's regulators, which have cracked down on practices of heavy discounting and delayed supplier ...