diff --git a/applications/solvers/multiphase/multiphaseEulerFoam/phaseSystems/diameterModels/velocityGroup/sizeGroup/shapeModels/fractal/fractal.C b/applications/solvers/multiphase/multiphaseEulerFoam/phaseSystems/diameterModels/velocityGroup/sizeGroup/shapeModels/fractal/fractal.C
index 147fdae683..e56019fe73 100644
--- a/applications/solvers/multiphase/multiphaseEulerFoam/phaseSystems/diameterModels/velocityGroup/sizeGroup/shapeModels/fractal/fractal.C
+++ b/applications/solvers/multiphase/multiphaseEulerFoam/phaseSystems/diameterModels/velocityGroup/sizeGroup/shapeModels/fractal/fractal.C
@@ -206,7 +206,6 @@ void Foam::diameterModels::shapeModels::fractal::correct()
     fvScalarMatrix kappaEqn
     (
         fvm::ddt(alpha, fi, kappa_) + fvm::div(fAlphaPhi, kappa_)
-      - fvm::Sp(fvc::ddt(alpha, fi) + fvc::div(fAlphaPhi), kappa_)
       ==
       - sinteringModel_->R()
       + Su_
diff --git a/applications/solvers/multiphase/multiphaseEulerFoam/phaseSystems/populationBalanceModel/populationBalanceModel/populationBalanceModel.C b/applications/solvers/multiphase/multiphaseEulerFoam/phaseSystems/populationBalanceModel/populationBalanceModel/populationBalanceModel.C
index d22e0da081..e442a878eb 100644
--- a/applications/solvers/multiphase/multiphaseEulerFoam/phaseSystems/populationBalanceModel/populationBalanceModel/populationBalanceModel.C
+++ b/applications/solvers/multiphase/multiphaseEulerFoam/phaseSystems/populationBalanceModel/populationBalanceModel/populationBalanceModel.C
@@ -1072,7 +1072,6 @@ void Foam::diameterModels::populationBalanceModel::solve()
                 fvScalarMatrix sizeGroupEqn
                 (
                     fvm::ddt(alpha, fi) + fvm::div(phase.alphaPhi(), fi)
-                  - fvm::Sp(fvc::ddt(alpha) + fvc::div(phase.alphaPhi()), fi)
                 ==
                     Su_[i]
                   - fvm::Sp(Sp_[i], fi)
diff --git a/tutorials/multiphase/multiphaseEulerFoam/RAS/wallBoilingPolydisperse/system/fvSolution b/tutorials/multiphase/multiphaseEulerFoam/RAS/wallBoilingPolydisperse/system/fvSolution
index abc735062b..772b122868 100644
--- a/tutorials/multiphase/multiphaseEulerFoam/RAS/wallBoilingPolydisperse/system/fvSolution
+++ b/tutorials/multiphase/multiphaseEulerFoam/RAS/wallBoilingPolydisperse/system/fvSolution
@@ -28,7 +28,7 @@ solvers
         tolerance               1e-4;
         scale                   true;
         solveOnFinalIterOnly    true;
-        sourceUpdateInterval    20;
+        sourceUpdateInterval    1;
     }
 
     p_rgh
diff --git a/tutorials/multiphase/multiphaseEulerFoam/RAS/wallBoilingPolydisperseTwoGroups/system/fvSolution b/tutorials/multiphase/multiphaseEulerFoam/RAS/wallBoilingPolydisperseTwoGroups/system/fvSolution
index abc735062b..772b122868 100644
--- a/tutorials/multiphase/multiphaseEulerFoam/RAS/wallBoilingPolydisperseTwoGroups/system/fvSolution
+++ b/tutorials/multiphase/multiphaseEulerFoam/RAS/wallBoilingPolydisperseTwoGroups/system/fvSolution
@@ -28,7 +28,7 @@ solvers
         tolerance               1e-4;
         scale                   true;
         solveOnFinalIterOnly    true;
-        sourceUpdateInterval    20;
+        sourceUpdateInterval    1;
     }
 
     p_rgh