diff --git a/include/robot_costmap_2d/voxel_layer.h b/include/robot_costmap_2d/voxel_layer.h
index bcfd113..a234d1e 100755
--- a/include/robot_costmap_2d/voxel_layer.h
+++ b/include/robot_costmap_2d/voxel_layer.h
@@ -126,6 +126,7 @@ private:
     double azimuth = 0.0;         ///< beam direction in the global frame
     double best_row_delta = std::numeric_limits<double>::infinity();
     bool has_ray = false;         ///< column had at least one readable pixel
+    bool in_left_border = false;  ///< column lies in the left no-disparity strip
   };
   std::vector<DepthColumnStat> depth_column_stats_;
   unsigned int unknown_threshold_, mark_threshold_, size_z_;
diff --git a/plugins/voxel_layer.cpp b/plugins/voxel_layer.cpp
index 78aa738..11509dc 100755
--- a/plugins/voxel_layer.cpp
+++ b/plugins/voxel_layer.cpp
@@ -739,19 +739,22 @@ bool VoxelLayer::raytraceDepthFrustum(const DepthCameraObservation& observation,
 
   for (const DepthRay& local_ray : depth_ray_cache_)
   {
-    // Skip the left-edge stereo no-disparity strip: those columns are
-    // permanently invalid, so clearing through them erases obstacles rotating
-    // out of the FOV on that side. Marking has no data there either, so nothing
-    // is lost. Invalid pixels ELSEWHERE still clear to max_range (ghost removal
-    // when an obstacle leaves and only far / open space remains behind it).
-    if (local_ray.u < frustum.clear_left_border_px)
-      continue;
-
     double depth_m = 0.0;
     bool valid = false;
     if (!readDepthMeters(depth, local_ray.u, local_ray.v, depth_m, valid))
       continue;
 
+    // Left-edge stereo no-disparity strip. An INVALID pixel here is structurally
+    // invalid (carries no free-space evidence), so clearing it out to max_range
+    // erases obstacles rotating out of the FOV on that side (the CW-turn bug) —
+    // skip only those. A VALID return here is a real measured surface, so it must
+    // still clear normally; otherwise the whole left border becomes a clearing
+    // dead zone and obstacles there never get cleared. Invalid pixels OUTSIDE the
+    // strip still clear to max_range (ghost removal).
+    const bool in_left_border = local_ray.u < frustum.clear_left_border_px;
+    if (in_left_border && !valid)
+      continue;
+
     // depth images store z-depth; local_ray.z is the unit ray's optical axis
     // component, so depth / z is the Euclidean range
     const double euclid_range = valid ? depth_m / local_ray.z : 0.0;
@@ -776,6 +779,8 @@ bool VoxelLayer::raytraceDepthFrustum(const DepthCameraObservation& observation,
           stat.best_row_delta = row_delta;
         }
         stat.has_ray = true;
+        if (in_left_border)
+          stat.in_left_border = true;
 
         if (valid)
         {
@@ -899,6 +904,13 @@ bool VoxelLayer::clearDepthColumns(double ox, double oy, double cover_distance,
     if (!stat.has_ray)
       continue;
 
+    // In the left stereo strip, never clear a whole column out to max_range on a
+    // missing in-band return: that is exactly the no-free-space-evidence case that
+    // erases obstacles turning out of view. Only an in-band measured surface may
+    // shorten (and thus clear) a border column.
+    if (stat.in_left_border && stat.min_band_dist < 0.0)
+      continue;
+
     double end_dist = stat.min_band_dist >= 0.0 ? stat.min_band_dist - skip_dist : max_range;
     end_dist = std::min(std::min(end_dist, max_range), far_distance);
     if (end_dist <= start_dist)