diff --git a/pcbnew/router/pns_utils.cpp b/pcbnew/router/pns_utils.cpp
index f155915461..57bf80f7da 100644
--- a/pcbnew/router/pns_utils.cpp
+++ b/pcbnew/router/pns_utils.cpp
@@ -271,7 +271,7 @@ void HullIntersection( const SHAPE_LINE_CHAIN& hull, const SHAPE_LINE_CHAIN& lin
 
     hull.Intersect( line, ips_raw );
 
-    for( const auto& p : ips_raw )
+    for( auto& p : ips_raw )
     {
         SHAPE_LINE_CHAIN::INTERSECTION ipp;
 
@@ -289,6 +289,9 @@ void HullIntersection( const SHAPE_LINE_CHAIN& hull, const SHAPE_LINE_CHAIN& lin
             continue;
         }
 
+        if( p.index_our >= hull.SegmentCount() )
+            p.index_our -= hull.SegmentCount();
+
         if( p.is_corner_our )
         {
             d1[0] = hull.CSegment( p.index_our );
@@ -340,4 +343,4 @@ void HullIntersection( const SHAPE_LINE_CHAIN& hull, const SHAPE_LINE_CHAIN& lin
     }
 }
 
-}
\ No newline at end of file
+}