diff --git a/dune/contact/common/gapfunction.cc b/dune/contact/common/gapfunction.cc
index 3631156807532e0527716d2bc511c6f5837dbbd3..7b237436e4e20a083cd3b6e5a3c98933cde18e70 100644
--- a/dune/contact/common/gapfunction.cc
+++ b/dune/contact/common/gapfunction.cc
@@ -428,7 +428,7 @@ void GapFunction<GridType,field_type>::firstDerivative(const VectorType& nonmort
 
         for (size_t i=0; i<mSize;i++)
             AnalyticLocalIntersectionAssembler<GlueType,MatrixType>::linearisedForwardProjection(
-                  linVertex[i],projVertex[i],size0, size0+size1, mglobalIdx[i]-size0, mCorners[i],
+                  linVertex[i],projVertex[i],size0, 0, size0+size1, mglobalIdx[i]-size0, mCorners[i],
                   avNormalsM[mglobalIdx[i]-size0],avNormMortarDeriv[globalToLocalM[mglobalIdx[i]-size0]],
                 nmglobalIdx, nmCorners[0], nmEdges,nmNormal);