diff --git a/src/finiteVolume/finiteVolume/ddtSchemes/ddtScheme/ddtScheme.C b/src/finiteVolume/finiteVolume/ddtSchemes/ddtScheme/ddtScheme.C
index 45bc97047e..4b201d9d3b 100644
--- a/src/finiteVolume/finiteVolume/ddtSchemes/ddtScheme/ddtScheme.C
+++ b/src/finiteVolume/finiteVolume/ddtSchemes/ddtScheme/ddtScheme.C
@@ -175,12 +175,28 @@ tmp<surfaceScalarField> ddtScheme<Type>::fvcDdtPhiCoeff
 
     if (ddtPhiCoeff_ < 0)
     {
+        // v1712 and earlier
+        // ddtCouplingCoeff -= min
+        // (
+        //     mag(phiCorr)
+        //    /(mag(phi) + dimensionedScalar("small", phi.dimensions(), SMALL)),
+        //     scalar(1)
+        // );
+
+        // See note below re: commented code
         ddtCouplingCoeff -= min
         (
+            // mag(phiCorr)
+            //*mesh().time().deltaT()*mag(mesh().deltaCoeffs())/mesh().magSf(),
+            // scalar(1)
             mag(phiCorr)
            *mesh().time().deltaT()*mesh().deltaCoeffs()/mesh().magSf(),
             scalar(1)
         );
+
+        // Note: setting oriented to false to avoid having to use mag(deltaCoeffs)
+        // - the deltaCoeffs field is always positive (scalars)
+        ddtCouplingCoeff.setOriented(false);
     }
     else
     {
diff --git a/src/finiteVolume/fvMesh/singleCellFvMesh/singleCellFvMesh.C b/src/finiteVolume/fvMesh/singleCellFvMesh/singleCellFvMesh.C
index 03e18d9a05..1fadf245ef 100644
--- a/src/finiteVolume/fvMesh/singleCellFvMesh/singleCellFvMesh.C
+++ b/src/finiteVolume/fvMesh/singleCellFvMesh/singleCellFvMesh.C
@@ -268,19 +268,20 @@ void Foam::singleCellFvMesh::agglomerateMesh
     }
     addFvPatches(newPatches);
 
+    const label nFace = patchFaces.size();
+
     // Actually change the mesh. // Owner, neighbour is trivial
     resetPrimitives
     (
         autoPtr<pointField>::New(std::move(boundaryPoints)),
         autoPtr<faceList>::New(std::move(patchFaces)),
-        autoPtr<labelList>::New(patchFaces.size(), Zero),  // owner
-        autoPtr<labelList>::New(),                         // neighbour
+        autoPtr<labelList>::New(nFace, Zero),   // owner
+        autoPtr<labelList>::New(),              // neighbour
         patchSizes,
         patchStarts,
-        true                //syncPar
+        true                                    // syncPar
     );
 
-
     // Adapt the zones
     cellZones().clear();
     cellZones().setSize(mesh.cellZones().size());