BRepFeat_SplitShape split Irregular TopAbs_FACE

I want to split an  Irregular TopAbs_FACE,the aS1 is an  Irregular TopAbs_FACE  and the aS2 is  formed by four TopAbs_FACE（colsed）.

the aInterCurve2 is  a Closed curve which are formed by four TopAbs_EDGE .

I add the four edge and face to the split ,however ,An Exception Thrown in Split2.Build();

I don't know why this happen,I check my code for many times,suprprisely ,in some shape my code performed successly ,but in the Irregular TopAbs_FACE ,it failed.

please tell how it happen ,thank you !

TopTools_ListOfShape GraphicalCalculation::DoSplit2(TopoDS_Shape aS1,
	TopoDS_Shape aS2)
{
   TopTools_ListOfShape  ValidLists;
   BRepAlgoAPI_Section sec2(aS1, aS2, Standard_False);
   sec2.SetRunParallel(Standard_True);
   sec2.SetFuzzyValue(aFuzzyValue);
   Standard_Integer iErr;
   sec2.ComputePCurveOn1(Standard_True);
   sec2.Build();
   iErr = sec2.ErrorStatus();
   if (iErr) {
       // an error treatment
       cout << "an error treatment" << endl;
       return ValidLists;
   }
   TopoDS_Shape aInterCurve2 = sec2.Shape();
   for (TopExp_Explorer exFace(aS1, TopAbs_FACE); exFace.More(); exFace.Next())
   {
	   TopoDS_Face aFace = TopoDS::Face(exFace.Current());
	   BRepFeat_SplitShape Split2 = BRepFeat_SplitShape(aFace);
	   for (TopExp_Explorer exEdge(aInterCurve2, TopAbs_EDGE); exEdge.More(); exEdge.Next())
	   {
		   TopoDS_Edge aE = TopoDS::Edge(exEdge.Current());
		   TopoDS_Shape aF = TopoDS_Shape();
		   if (sec2.HasAncestorFaceOn1(aE, aF))
		   {
			   TopoDS_Face aAncFace = TopoDS::Face(aF);
			   if (aAncFace.IsSame(aFace))
			   {
				  Split2.Add(aE, aAncFace);
			   } 
		   }
		   try
		   {
			   Split2.Build();
		   }
		   catch (Standard_Failure)
		   {
			   cout << "An Exception Thrown! " << endl;
		   }
		
		   for (TopExp_Explorer exface2(Split2.Shape(), TopAbs_FACE); exface2.More(); exface2.Next())
		   {
			   ValidLists.Append(exface2.Current());
		   }
	   }
   }
	return ValidLists;

}