SBF always maintained that FTX was over-collateralized. But now it turns out that was based on daily average withdrawal rate, not total accounts. So when tons of people tried to withdraw at once, it was proven that FTX was actually under-collateralized. He knew this was the case the whole time.

The real mistake he made was thinking he could use an accounting trick to defraud people forever. Accounting tricks always blow up in your face sooner or later.