Could not get intersection for two overlapping circles

Code in question:

#include <cstdio>

#include <Geom2d_Circle.hxx>
#include <Geom2d_Line.hxx>
#include <Geom2dAPI_InterCurveCurve.hxx>
#include <gp_Circ2d.hxx>


gp_Ax2d make_axis2d(Standard_Real x, Standard_Real y) {
    return gp_Ax2d(gp_Pnt2d(x, y), gp_Dir2d(1, 0));
}

int main() {
    gp_Circ2d gc1 = gp_Circ2d(make_axis2d(0, 0), 10);
    gp_Circ2d gc2 = gp_Circ2d(make_axis2d(5, 0), 10);
    gp_Circ2d gc3 = gp_Circ2d(make_axis2d(10, 0), 10);

    Handle(Geom2d_Circle) c1 = new Geom2d_Circle(gc1);
    Handle(Geom2d_Circle) c2 = new Geom2d_Circle(gc2);
    Handle(Geom2d_Circle) c3 = new Geom2d_Circle(gc3);

    Geom2dAPI_InterCurveCurve Intersector1(c1, c2, 10e-6); 
    Standard_Integer N = Intersector1.NbPoints();
    printf("Intersections c1 vs c2: %i\n", N);
    for (int i=1; i<=N; i++){
        auto pt = Intersector1.Point(i);
        printf("  %f %f\n", pt.X(), pt.Y());
    }

    Geom2dAPI_InterCurveCurve Intersector2(c1, c3, 10e-6); 
    N = Intersector2.NbPoints();
    printf("Intersections c1 vs c3: %i\n", N);
    for (int i=1; i<=N; i++){
        auto pt = Intersector2.Point(i);
        printf("  %f %f\n", pt.X(), pt.Y());
    }
}

Output:

Intersections c1 vs c2: 0
Intersections c1 vs c3: 2
  5.000000 -8.660254
  5.000000 8.660254

All circles are overlapping, radius 10, centers are on Y axis, with Xs: 0, 5, 10. But I get intersection points only for c1 and c3. I've tried 7.7 and 7.8 lib versions. What am I missing?