Not only that, I believe they had to exchange the ETH for USD before the auction to prove their holding. They now need to turn the USD back to ETH. ETH crashed by about 10% yesterday afternoon (which could be due to them liquidating that much ETH, that would be a big story itself) and so they will have lost a fair bit there!
I think FTX agreed to return the same amount of ETH regardless of fx rates but let’s see. ETH daily volume is over $20b wouldn’t have made a material difference.