Trade management functions run at every tick, which implies some restrictions. Indicators that create data series can not be called in a TMF; other indicators can be called. The current candle is incomplete, so its range and height is smaller than the other candles; and the last full candle has the index 1, not 0. The price functions can be called, but make no much sense for the current bar because the open, high, or low prices are in relation to the bar boundary. Use TradePriceOpen or TradePriceClose for evaluating the current price of the asset.