Just like we knew for at least a year already about the sales through Singapore. A lot of people called it for what it is at the time already (see for example: https://www.ft.com/content/6b1ce190-24d4-4f39-a518-ef9dae5fa...). And yet, things unrolled very slowly, then suddenly.
My theory is that once new CEO is found, especially if he comes from the outside, he will be highly incentivized to denounce past sins and disclose as much as possible to start with a clean sheet. I would bet that this is one of the main reasons the stock is tanking. House of cards is about to collapse, and that may be the trigger.