I am also having this same problem too. It is happening specifically with fiat / USD buys. It seems to be a glitch with the way Koinly is importing CSV files. I think I have found a temporary workaround. Open the CSV in Excel or similar. Sort spreadsheet by the category column so all of the straight “buys” are together. Then change “buy” to “sell” under both the columns “category” and “operation” and copy paste all the way down your buys. Then sort the spreedsheet back into its original order by date, export as corrected CSV, then import into Koinly. To avoid duplicating other transactions, it’s probably best to just erase the BinanceUS wallet and import everything over. It’s a pain. But I don’t have too many transactions. Under a 1000. I can imagine this being a nightmare with more.