Incorrect Fitness value for stock symbols

[ys2310]

With stock symbols, somehow I always get the backtest result fitness value as 0.
Following is an exmple output of a stock backtest.
I tried to define my custom GetFitness() function and that didn't work either.

Info | CBot instance [STOCK_TriangleArb, SALVATORE FERRAGAMO, m1] stopped.
{
"Equity":90184,
"NetProfit":4682,
"MaxBalanceDrawdownPercentages":0,
"MaxEquityDrawdownPercentages":20,
"MaxBalanceDrawdown":0,
"MaxEquityDrawdown":22107,
"WinningTrades":3,
"LosingTrades":0,
"TotalTrades":3,
"AverageTrade":1560,
"ProfitFactor":-,
"Fitness":0
}