diff --git a/src/BRepLib/BRepLib.cxx b/src/BRepLib/BRepLib.cxx
index 1bc4318172..f891ab9b60 100644
--- a/src/BRepLib/BRepLib.cxx
+++ b/src/BRepLib/BRepLib.cxx
@@ -1899,6 +1899,10 @@ Standard_Boolean BRepLib::
     TShort_Array1OfShortReal& aNormArr1 = aPT1->ChangeNormals();
     TShort_Array1OfShortReal& aNormArr2 = aPT2->ChangeNormals();
 
+    if (aPTEF1->Nodes().Lower() != aPTEF2->Nodes().Lower() || 
+        aPTEF1->Nodes().Upper() != aPTEF2->Nodes().Upper()) 
+      continue; 
+
     for(Standard_Integer anEdgNode = aPTEF1->Nodes().Lower();
                          anEdgNode <= aPTEF1->Nodes().Upper(); anEdgNode++)
     {
diff --git a/tests/bugs/modalg_6/bug27391 b/tests/bugs/modalg_6/bug27391
new file mode 100644
index 0000000000..7b8905f26e
--- /dev/null
+++ b/tests/bugs/modalg_6/bug27391
@@ -0,0 +1,10 @@
+puts "============"
+puts "OCC27391"
+puts "============"
+puts ""
+######################################################
+# BRepLib::EnsureNormalConsistency() raises exception in case of asynchronious PolygonOnTriangulation problem
+######################################################
+
+restore [locate_data_file bug27391_Ficomirrors_ExportBinMoldflow.brep] a
+correctnormals a