diff --git a/src/Geom/Geom_RectangularTrimmedSurface.cxx b/src/Geom/Geom_RectangularTrimmedSurface.cxx
index e7ff92fe8f..69bb5b3ea5 100644
--- a/src/Geom/Geom_RectangularTrimmedSurface.cxx
+++ b/src/Geom/Geom_RectangularTrimmedSurface.cxx
@@ -118,7 +118,7 @@ const Standard_Boolean          VSense)
   {
     Handle(Geom_RectangularTrimmedSurface) S2 = 
            new Geom_RectangularTrimmedSurface( O->BasisSurface(),U1,U2, V1, V2, USense, VSense);
-    basisSurf = new Geom_OffsetSurface(S2, O->Offset());
+    basisSurf = new Geom_OffsetSurface(S2, O->Offset(), Standard_True);
   }  
 
   SetTrim( U1, U2, V1, V2, USense, VSense);
@@ -153,7 +153,7 @@ Geom_RectangularTrimmedSurface::Geom_RectangularTrimmedSurface (
   {
     Handle(Geom_RectangularTrimmedSurface) S2 = 
            new Geom_RectangularTrimmedSurface( O->BasisSurface(),Param1,Param2, UTrim, Sense);
-    basisSurf = new Geom_OffsetSurface(S2, O->Offset());
+    basisSurf = new Geom_OffsetSurface(S2, O->Offset(), Standard_True);
   }  
 
   SetTrim(Param1, Param2, UTrim, Sense);
diff --git a/tests/bugs/modalg_7/bug31430 b/tests/bugs/modalg_7/bug31430
new file mode 100644
index 0000000000..0a1c7e22e4
--- /dev/null
+++ b/tests/bugs/modalg_7/bug31430
@@ -0,0 +1,10 @@
+puts "========"
+puts "0031430: Modeling Data - Offset surfaces on C1 surfaces (with multiplicity equal to degree) may still throw ex-ception"
+puts "========"
+puts ""
+
+restore [locate_data_file bug31430.brep] s
+fixshape r s
+
+checkshape r
+checknbshapes r -vertex 6 -edge 8 -wire 6 -face 4 -shell 1 -solid 1