When the CEO makes a bunch of fraudulent statements, that is actually bad. It's one thing for people to change jobs, it's another when the guy who is the direct line of fire from Musk's lies leaves. The market can stay irrational for a long time, but at some point reality will enter the equation.
You can only keep the corruption going for so long. Maybe there's someone new at the SEC that will actually go after him, maybe the shareholder have finally had enough. It could be anything but the CFO headed for the door in a company notorious for fraud speaks to a potential reckoning.