The real USDtb isn’t available on BNB Chain and is unrelated to Tether, so that was one red flag. Another red flag is that it doesn’t make sense to swap one stablecoin to another through a forum and with a 20% discount. If it’s a legitimate token, there should be liquidity pools on decentralized exchanges where you can trade it at a nearly 1:1 ratio with other stablecoins. Technically, there is some DEX liquidity, but it’s only around $4, which is why it was way off peg.