This is not actually the first time that this kind of trades is taking place, it usually happen especially on binance exchange as I have observed it a few times. As of last year, there was also a spike in the price of Bitcoin where some sold for a very high price (more than 30%) of the current price, I believe it's the buyer that makes such mistake by setting a buy order at a high price and if there's also a seller's order that match that of the buyer, it's going to execute. Just uncommon mistakes that few people make at time.