diff --git a/Operations_on_polyhedra/include/CGAL/internal/corefinement/Polyhedra_output_builder.h b/Operations_on_polyhedra/include/CGAL/internal/corefinement/Polyhedra_output_builder.h
index 27f711bf00d..a4c5e2f23f8 100644
--- a/Operations_on_polyhedra/include/CGAL/internal/corefinement/Polyhedra_output_builder.h
+++ b/Operations_on_polyhedra/include/CGAL/internal/corefinement/Polyhedra_output_builder.h
@@ -2203,7 +2203,7 @@ public:
 
       P_polylines.push_back(phedge);
       Q_polylines.push_back(qhedge);
-      polyline_lengths.push_back(polyline_info.second-1);
+      polyline_lengths.push_back(polyline_info.second+1);
     }
 
     //store the patch description in a container to avoid recomputing it several times
diff --git a/Operations_on_polyhedra/include/CGAL/intersection_of_Polyhedra_3.h b/Operations_on_polyhedra/include/CGAL/intersection_of_Polyhedra_3.h
index 1ef348e47b8..2fa63da8c9a 100644
--- a/Operations_on_polyhedra/include/CGAL/intersection_of_Polyhedra_3.h
+++ b/Operations_on_polyhedra/include/CGAL/intersection_of_Polyhedra_3.h
@@ -1771,7 +1771,7 @@ class Intersection_of_Polyhedra_3{
     //handle polylines
     while(terminal_nodes.any())
     {
-      int i= static_cast<int>(terminal_nodes.find_first());
+      int i = static_cast<int>(terminal_nodes.find_first());
       Graph_node& node_i = graph[i];
       std::vector<typename Kernel::Point_3> polyline;
 
@@ -1782,14 +1782,12 @@ class Intersection_of_Polyhedra_3{
       if (node_i.empty())
         terminal_nodes.reset(i);
       polyline.push_back(nodes[i]);
-      visitor->add_node_to_polyline(i);
       while(true){
         Graph_node& node_j=graph[j];
         CGAL_assertion(!node_j.empty());
         node_j.erase(i);
         i=j;
         polyline.push_back(nodes[i]);
-        visitor->add_node_to_polyline(i);
         if (node_j.is_terminal())
         {
           if (node_j.empty())
@@ -1798,6 +1796,7 @@ class Intersection_of_Polyhedra_3{
         }
         else{
           j=node_j.top();
+          visitor->add_node_to_polyline(j);
           node_j.pop();
           CGAL_assertion(node_j.empty());
           interior_nodes.reset(i);
@@ -1817,7 +1816,6 @@ class Intersection_of_Polyhedra_3{
       visitor->start_new_polyline(i,j);
       interior_nodes.reset(i);
       polyline.push_back(nodes[i]);
-      visitor->add_node_to_polyline(i);
       int first=i;
       do{
         Graph_node& node_j=graph[j];
@@ -1825,11 +1823,10 @@ class Intersection_of_Polyhedra_3{
         node_j.erase(i);
         i=j;
         polyline.push_back(nodes[i]);
-        visitor->add_node_to_polyline(i);
         j=node_j.top();
+        visitor->add_node_to_polyline(j);
       }while(j!=first);
       polyline.push_back(nodes[j]);// we duplicate first point for cycles
-      visitor->add_node_to_polyline(j);
       *out++=polyline;
     }
   }
diff --git a/Polygon_mesh_processing/include/CGAL/Polygon_mesh_processing/internal/Corefinement/Face_graph_output_builder.h b/Polygon_mesh_processing/include/CGAL/Polygon_mesh_processing/internal/Corefinement/Face_graph_output_builder.h
index e89ed6b09f9..786e95da07a 100644
--- a/Polygon_mesh_processing/include/CGAL/Polygon_mesh_processing/internal/Corefinement/Face_graph_output_builder.h
+++ b/Polygon_mesh_processing/include/CGAL/Polygon_mesh_processing/internal/Corefinement/Face_graph_output_builder.h
@@ -1006,7 +1006,7 @@ public:
 
       tm1_polylines.push_back(h1);
       tm2_polylines.push_back(h2);
-      polyline_lengths.push_back(polyline_info.second-1);
+      polyline_lengths.push_back(polyline_info.second+1);
     }
 
     typedef Patch_container<TriangleMesh,
diff --git a/Polygon_mesh_processing/include/CGAL/Polygon_mesh_processing/internal/Corefinement/intersection_impl.h b/Polygon_mesh_processing/include/CGAL/Polygon_mesh_processing/internal/Corefinement/intersection_impl.h
index 9952deb6436..25a8b51faf5 100644
--- a/Polygon_mesh_processing/include/CGAL/Polygon_mesh_processing/internal/Corefinement/intersection_impl.h
+++ b/Polygon_mesh_processing/include/CGAL/Polygon_mesh_processing/internal/Corefinement/intersection_impl.h
@@ -741,14 +741,12 @@ class Intersection_of_triangle_meshes
       if (node_i.empty())
         terminal_nodes.reset(i);
       polyline.push_back(nodes[i]);
-      visitor.add_node_to_polyline(i);
       while(true){
         Graph_node& node_j=graph[j];
         CGAL_assertion(!node_j.empty());
         node_j.erase(i);
         i=j;
         polyline.push_back(nodes[i]);
-        visitor.add_node_to_polyline(i);
         if (node_j.is_terminal())
         {
           if (node_j.empty())
@@ -757,6 +755,7 @@ class Intersection_of_triangle_meshes
         }
         else{
           j=node_j.top();
+          visitor.add_node_to_polyline(j);
           node_j.pop();
           CGAL_assertion(node_j.empty());
           interior_nodes.reset(i);
@@ -776,7 +775,6 @@ class Intersection_of_triangle_meshes
       visitor.start_new_polyline(i,j);
       interior_nodes.reset(i);
       polyline.push_back(nodes[i]);
-      visitor.add_node_to_polyline(i);
       Node_id first=i;
       do{
         Graph_node& node_j=graph[j];
@@ -784,11 +782,10 @@ class Intersection_of_triangle_meshes
         node_j.erase(i);
         i=j;
         polyline.push_back(nodes[i]);
-        visitor.add_node_to_polyline(i);
         j=node_j.top();
+        visitor.add_node_to_polyline(j);
       }while(j!=first);
       polyline.push_back(nodes[j]);// we duplicate first point for cycles
-      visitor.add_node_to_polyline(j);
       *out++=polyline;
     }
   }