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 c9eed95cef6..1744127500a 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
@@ -611,9 +611,15 @@ public:
         ++epp_it;
     }
     BOOST_FOREACH(edge_descriptor ed, inter_edges_to_remove1)
+    {
+      put(marks_on_input_edges.ecm1, ed, false);
       intersection_edges1.erase(ed);
+    }
     BOOST_FOREACH(edge_descriptor ed, inter_edges_to_remove2)
+    {
+      put(marks_on_input_edges.ecm2, ed, false);
       intersection_edges2.erase(ed);
+    }
 
     // (1) Assign a patch id to each facet indicating in which connected
     // component limited by intersection edges of the surface they are.
diff --git a/Segment_Delaunay_graph_2/include/CGAL/Segment_Delaunay_graph_2/Basic_predicates_C2.h b/Segment_Delaunay_graph_2/include/CGAL/Segment_Delaunay_graph_2/Basic_predicates_C2.h
index fab693cce20..6eb2fd2e803 100644
--- a/Segment_Delaunay_graph_2/include/CGAL/Segment_Delaunay_graph_2/Basic_predicates_C2.h
+++ b/Segment_Delaunay_graph_2/include/CGAL/Segment_Delaunay_graph_2/Basic_predicates_C2.h
@@ -143,8 +143,11 @@ public:
   static
   FT to_ft(const Sqrt_3& x)
   {
-    FT sqrt_e = compute_sqrt( to_ft(x.e()), FT_Has_sqrt() );
-    FT sqrt_f = compute_sqrt( to_ft(x.f()), FT_Has_sqrt() );
+    // If the number type does not offer a square root, x.e() and x.f() (which are of type sqrt_1)
+    // might be negative after (approximately) evaluating them. Taking the max sanitize these values
+    // to ensure that we do not take the square root of a negative number.
+    FT sqrt_e = compute_sqrt( (std::max)(FT(0), to_ft(x.e())), FT_Has_sqrt() );
+    FT sqrt_f = compute_sqrt( (std::max)(FT(0), to_ft(x.f())), FT_Has_sqrt() );
     FT sqrt_ef = sqrt_e * sqrt_f;
     return to_ft(x.a()) + to_ft(x.b()) * sqrt_e
       + to_ft(x.c()) * sqrt_f + to_ft(x.d()) * sqrt_ef;