diff --git a/Frechet_distance/include/CGAL/Frechet_distance/internal/Frechet_light.h b/Frechet_distance/include/CGAL/Frechet_distance/internal/Frechet_light.h
index 46e91745821..57bd1305cc5 100644
--- a/Frechet_distance/include/CGAL/Frechet_distance/internal/Frechet_light.h
+++ b/Frechet_distance/include/CGAL/Frechet_distance/internal/Frechet_light.h
@@ -514,6 +514,7 @@ inline void FrechetLight<C>::continueQSimpleSearch(QSimpleInterval& qsimple,
         // TODO: uncritical for correctness or speed but unelegant coding style: stripping down information added by getInterval
         CInterval temp_interval = FrechetLight::getInterval<IndexType>(
             fixed_curve, fixed, curve, cur);
+
         Interval interval = Interval(temp_interval.begin.getPoint() == cur
                                          ? temp_interval.begin.getFraction()
                                          : 1,
diff --git a/Frechet_distance/include/CGAL/Frechet_distance/internal/geometry_basics.h b/Frechet_distance/include/CGAL/Frechet_distance/internal/geometry_basics.h
index f7cf9f72548..8dec6273f8a 100644
--- a/Frechet_distance/include/CGAL/Frechet_distance/internal/geometry_basics.h
+++ b/Frechet_distance/include/CGAL/Frechet_distance/internal/geometry_basics.h
@@ -113,7 +113,10 @@ struct Lambda<Curve<FilteredTraits,true>>
     //     fill_lambda returns a pair and we are only interested in a bound
     bool update_exact() const
     {
-        if (is_exact) {
+        if (is_exact){
+            if (!exact.has_value()){
+                exact = (is_one) ? std::make_optional(Exact(1)) : std::make_optional(Exact(0));
+            }
             return true;
         }
 
@@ -198,7 +201,9 @@ struct Lambda<Curve<FilteredTraits,true>>
     {
         if ((is_zero && other.is_zero) || (is_one && other.is_one))
             return false;
-        if ((is_zero && (!other.is_zero)) || (!is_one && other.is_one))
+        // AF this may be wrong if approx is [0.9,1.1]  and other.is_one:
+        // if ((is_zero && (!other.is_zero)) || (!is_one && other.is_one))
+        if(is_zero && other.is_one)
             return true;
         CGAL::Uncertain<bool> res = approx < other.approx;
         if (CGAL::is_certain(res)) {
@@ -206,7 +211,8 @@ struct Lambda<Curve<FilteredTraits,true>>
         }
         update_exact();
         other.update_exact();
-        return exact < other.exact;
+        bool eres = exact.value() < other.exact.value();
+        return eres;
     }
 };
 
diff --git a/Frechet_distance/test/Frechet_distance/CMakeLists.txt b/Frechet_distance/test/Frechet_distance/CMakeLists.txt
index 9a489adcc6f..fdf7fc6d1a6 100644
--- a/Frechet_distance/test/Frechet_distance/CMakeLists.txt
+++ b/Frechet_distance/test/Frechet_distance/CMakeLists.txt
@@ -6,6 +6,9 @@ project( Frechet_distance_Tests )
 
 find_package(CGAL REQUIRED)
 
+
+create_single_source_cgal_program( "Frechet-IssueOct25.cpp" )
+
 find_package(Eigen3 3.1.0 QUIET) #(3.1.0 or greater)
 include(CGAL_Eigen3_support)
 if(TARGET CGAL::Eigen3_support)
diff --git a/Frechet_distance/test/Frechet_distance/Frechet-IssueOct25.cpp b/Frechet_distance/test/Frechet_distance/Frechet-IssueOct25.cpp
new file mode 100644
index 00000000000..ff753671a9f
--- /dev/null
+++ b/Frechet_distance/test/Frechet_distance/Frechet-IssueOct25.cpp
@@ -0,0 +1,40 @@
+#include <CGAL/Exact_predicates_inexact_constructions_kernel.h>
+#include <CGAL/Frechet_distance.h>
+
+#include <fstream>
+
+using Kernel = CGAL::Exact_predicates_inexact_constructions_kernel;
+using Point = Kernel::Point_2;
+using Segment = Kernel::Segment_2;
+
+bool load_polyline(const std::string &filename, std::vector<Point> &polyline) {
+  polyline.clear();
+  std::ifstream ifs(filename);
+
+  if (!ifs)
+    return false;
+
+  while (ifs.good()) {
+    Point p;
+    ifs >> p;
+    if (ifs.good())
+      polyline.push_back(p);
+  }
+
+  return true;
+}
+
+int main() {
+
+  std::vector<Point> poly1, poly2;
+
+  if (!load_polyline("poly1.txt", poly1) || !load_polyline("poly2.txt", poly2)) {
+    std::cout << "input files could not be loaded" << std::endl;
+    return -1;
+  }
+
+
+  std::pair<double, double> res = CGAL::bounded_error_Frechet_distance(poly1, poly2, 0.000001);
+ std::cout << "Frechet distance: [" << res.first << ", " << res.second << "]" << std::endl;
+  return 0;
+}
diff --git a/Frechet_distance/test/Frechet_distance/poly1.txt b/Frechet_distance/test/Frechet_distance/poly1.txt
new file mode 100644
index 00000000000..309937888c6
--- /dev/null
+++ b/Frechet_distance/test/Frechet_distance/poly1.txt
@@ -0,0 +1,185 @@
+-126 70
+-138 58
+-39 -18
+-39 -18
+-39 -18
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+-39 -18
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+-42.6 -14
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diff --git a/Frechet_distance/test/Frechet_distance/poly2.txt b/Frechet_distance/test/Frechet_distance/poly2.txt
new file mode 100644
index 00000000000..5317263ddb9
--- /dev/null
+++ b/Frechet_distance/test/Frechet_distance/poly2.txt
@@ -0,0 +1,625 @@
+-126 70
+70 -138
+70 -138
+70 -138
+70 -138
+70 -138
+70 -138
+70 -138
+70 -138
+70 -138
+70 -138
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+70 -138
+61.4 -118.4
+61.4 -118
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diff --git a/Stream_lines_2/include/CGAL/Regular_grid_2.h b/Stream_lines_2/include/CGAL/Regular_grid_2.h
index 2ef9c992a01..2e9eb33bc58 100644
--- a/Stream_lines_2/include/CGAL/Regular_grid_2.h
+++ b/Stream_lines_2/include/CGAL/Regular_grid_2.h
@@ -93,7 +93,7 @@ public:
 
 template <class StreamLinesTraits_2>
 inline
-typename Regular_grid_2<StreamLinesTraits_2>::Geom_traits::Iso_rectangle_2
+typename StreamLinesTraits_2::Iso_rectangle_2
 Regular_grid_2<StreamLinesTraits_2>::bbox() const
 {
   return typename Geom_traits::Iso_rectangle_2(0.0, 0.0,
diff --git a/Stream_lines_2/include/CGAL/Triangular_field_2.h b/Stream_lines_2/include/CGAL/Triangular_field_2.h
index 1dd733409c7..df6eb6807f4 100644
--- a/Stream_lines_2/include/CGAL/Triangular_field_2.h
+++ b/Stream_lines_2/include/CGAL/Triangular_field_2.h
@@ -134,7 +134,7 @@ protected:
 
 template <class StreamLinesTraits_2>
 inline
-typename Triangular_field_2<StreamLinesTraits_2>::Geom_traits::Iso_rectangle_2
+typename StreamLinesTraits_2::Iso_rectangle_2
 Triangular_field_2<StreamLinesTraits_2>::bbox() const
 {
   return typename Geom_traits::Iso_rectangle_2(minx, miny, maxx,