Kucoin API buy and sell Why, when I using Kucoin API, get_tick, for market info, I see, that sell is bigger buy?

Example from oficcial  API Documentation:
With a symbol param

{
    "coinType": "KCS",
    "trading": true,
    "lastDealPrice": 5040,
    "buy": 5000,
    "sell": 5040,
    "coinTypePair": "BTC",
    "sort": 0,
    "feeRate": 0.001,
    "volValue": 308140577,
    "high": 6890,
    "datetime": 1506050394000,
    "vol": 5028739175025,
    "low": 5040,
    "changeRate": -0.2642
}
"lastDealPrice": 5040,

"sell": 5040,


This means that the last price exchange happened is at 5040 and sell is at the same price, i.e. a sell order at that price has been executed and registered as "Last Deal Price", shich is acutally higher than the buy orders price.