Multi-symbol cBot bars doesn´t syncronized

Hello!

I´m having troubles accessing to diferents bars in my multi-symbol cBot. I get the bars of the following way, however when I check the OpenPrices.Last(1) in OnBar method, is said, the Datetime of the previous bar, the OpenPrices of both series differs. Only the bars data in serie A (for example) are correct when the primary Symbol (Chart Symbol) is the same than the serie (A for example).

Please, somebody can help me?!

 protected override void OnStart()
 { 
    ...
 	_seriesA = MarketData.GetBars(TimeFrame, _symbolA.Name); 
 	_seriesB = MarketData.GetBars(TimeFrame, _symbolB.Name); 
 	...
 }   
 protected override void OnBar()
 {
	// If serieB is distinct to primary Symbol, OpenPrices isn´t the same
    if (_seriesB.OpenTimes.Last(1).Date != Bars.OpenTimes.Last(1).Date)    
    {
    	Stop();
    }                                                                                                                   
     ....
  }