retreiving underlying circle object form an edge

As you see I am trying to retrieve the underlying curves of the fused face object between two similar circles.
The trouble occurs when I am trying to get the gp*_circ object of the curve witgh the line of code "gp_Circ circ = circle->Circ();"
so it seems there is something wrong with the casting, but th eexcact same code works perfectly fine for other circles.
anyone got any clue?

TopoDS_Shape Circle() {
gp_Pnt centerPt(0, 0, 0);
gp_Dir dir(0, 0, -1);
gp_Ax2 ax2(centerPt, dir);
gp_Circ circ(ax2, 5);

Geom_Curve* curve = new Geom_Circle(circ);
BRepBuilderAPI_MakeEdge maker(curve);
BRepBuilderAPI_MakeWire wire(maker.Edge());
BRepBuilderAPI_MakeFace face(wire.Wire());
return face.Face();
}

TopoDS_Shape Circle2() {
gp_Pnt centerPt(5, 0, 0);
gp_Dir dir(0, 0, -1);
gp_Ax2 ax2(centerPt, dir);
gp_Circ circ(ax2, 5);

Geom_Curve* curve = new Geom_Circle(circ);
BRepBuilderAPI_MakeEdge maker(curve);
BRepBuilderAPI_MakeWire wire(maker.Edge());
BRepBuilderAPI_MakeFace face(wire.Wire());
return face.Face();
}

TopoDS_Shape Fuse(TopoDS_Shape face1, TopoDS_Shape face2) {

BRepAlgoAPI_Fuse fuse(face1, face2);
fuse.SimplifyResult();
TopExp_Explorer faceExplorer(fuse.Shape(), TopAbs_FACE);

return fuse.Shape();
}

TopoDS_Shape Explorer(TopoDS_Shape shape) {
TopExp_Explorer faceExplorer = TopExp_Explorer(shape, TopAbs_FACE);
TopoDS_Face face = TopoDS::Face(faceExplorer.Current());
TopExp_Explorer edgeExplorer(face, TopAbs_EDGE);
TopoDS_Edge edge = TopoDS::Edge(edgeExplorer.Current());
edgeExplorer.Next();
Standard_Real first, last;
Handle(Geom_Curve) curve = BRep_Tool::Curve(edge, first, last);
Handle(Geom_TrimmedCurve) trimmedCurve = new Geom_TrimmedCurve(curve, first, last);
Handle(Geom_Circle) circle = Handle(Geom_Circle)::DownCast(curve);
gp_Circ circ = circle->Circ();
gp_Ax1 axis = circ.Axis();
gp_Dir dir = axis.Direction();
gp_Pnt center = circle->Location();
double radius = circle->Circ().Radius();
return edgeExplorer.Current();
}

TopoDS_Shape fuse = Fuse(circle, circle2);
TopoDS_Shape explorer = Explorer(fuse);