example:
Long position, stop loss is closed using the asking price.
Long position, take profit is closed using the biding price.
You can quickly test this with cTrader using a symbol with a wide-spread and setting a stop loss and take profit.
You will find this is standard with all trading platforms, this is how the bid/ask spread works, you can also Google this question, if you think about it, you will see it makes sense as the markup is made on both stops and profits.
https://www.investopedia.com/terms/b/bid-askspread.asp