Usually, you see profits like this on the History page. Profit in the selected currency (normally Quote currency):
1 - Sometimes there will be a negative value near a positive one.
It can be in the Base currency as well as in the Quote one. The amount could be positive too:
It's a healthy situation, and you aren't losing anything. There is nothing wrong with profit calculations and your final gain is shown below numbers in $. It includes the negative amount too if there is any. In other words, if the number below with $ is green and positive - the deal is closed in profit.
The main reasons for this are the trading fee and the exchange's limitations for the price step and volume step:
When the bot should buy 10.5 KEY, but the exchange limits the order size to an integer number, it should be 11 or 10. If the bot buys less (10 KEY), a negative amount in KEY will appear. And a positive one in a second currency from the pair. If the bot buys more (11 KEY), a negative amount in a second currency from the pair will appear. And a positive one in the KEY.
When the bot should buy 10 KEY for $0.015, but the exchange limits price step to two decimal places, so it should be $0.02 or $0.01. If the bot buys lower ($0.01), the number will be positive. If higher ($0.02) it will be negative.
To reduce this effect it's recommended to hold some BNBs to pay fees (for Binance), Take Profit should be set to Quote, and Order size should be increased.
2 - But if you see negative values in both fields, your deal indeed closed Take profit in loss.
This could happen only with Market Take profit (Conditional or with enabled Trailing):
the order was sent into exchange order-book, and filled all BIDs (if it is Long deal) on it`s way, so average sell price became even lower than the average buy price.
The reason for this:
Huge price drop
Low order-book
Too big order size for specific pair
Low presetted Take Profit percentage
Big presetted Trailing percentage comparing to Take Profit