Although the details change, the pattern stays the same. This time, the executive departure is David Morton, chief accounting officer at Tesla Inc., who called it quits after just a month on the job. The controversy is over Elon Musk taking a hit off an apparent marijuana-tobacco joint during a podcast interview that made its rounds on YouTube. And the stock dropped more than 6 percent Friday to close at $263.24 a share — its lowest point since March of last year.