I have this function that takes top and bottom values (Candle Index) as inputs and returns the candle index which has highest high between those two candles

// Function to find highest bar index within a specified window
f_find_highest_bar_index(bot, top) =>
    var float hi = 10e-10
    var float lo = 10e10
    var int highestBarIndex = na
    
    bool window = bar_index >= bot and bar_index <= int(top)

    if (window)
        if (high > hi)
            hi := high
            highestBarIndex := bar_index
        
        if (low < lo)
            lo := low

    // Return the highest bar index
    highestBarIndex 

Code works fine and returns 6670 currectly if i pass constant for top value (see image 1)

 top = 6671

But as soon as i pass variable retracementBarIndex in top variable, it returns wrong value 6672, while it should also return 6670. See second image

Cannot quire understand why is this happening?