
WHo knows, maybe there were a few whales looking to buy in the auction and, when they didn't win, decided to source them from elsewhere. Plausible?
Front running by insiders by knowing that 300Mio$ Tethers will be printed - price increased - you can't explain that
300Mio$ Tether will be used to pump BTC to 11k$ - you can't explain that

That too. PLus... assuming Teter was all legit (fully FIAT backed up) before needing to print an additional $300M they must have used (sold) as much Tether's were "refunded" and back to them during the downtrend. So it would not be just those new Tethers being reinserted into the market. More like "the tip of the iceberg".