It looks like an error on coinmarketcap in the KRW exchange rate (and probably the volumes are also wrong). If you look at the actual Upbit exchange for Steem / KRW the price does not get above 1,050 (so less than 1,114 which is the equivalent of $1).

Interestingly it looks like the issue did make Steem jump on other exchanges, including over 5% on Binance, although it has now fallen back almost all the way. It just shows you the power of the coinmarketcap website!