diff --git a/.gitlab-ci.yml b/.gitlab-ci.yml
index c3b269335307d151c7221f3a0f26217485f531d5..97272122c2ac8c87074a6bb92f7a1113dcb2d26b 100644
--- a/.gitlab-ci.yml
+++ b/.gitlab-ci.yml
@@ -11,22 +11,6 @@ stages:
 
 ###############################################################################
 ##                                Builds                                     ##
-###############################################################################
-gcc_9_python:
-  stage: build
-
-  cache:
-    key: "Python-GCC9-$CI_JOB_NAME-$CI_COMMIT_REF_SLUG"
-    paths:
-      - build
-
-  artifacts:
-    paths:
-      - dist/
-
-  script:
-    - python3 setup.py bdist_wheel
-
 ###############################################################################
 .gnu_build_template:
   stage: build
@@ -71,6 +55,22 @@ gcc_9:
   extends: .gnu_build_template
 
 ###############################################################################
+
+gcc_9_python:
+  stage: build
+
+  needs: ["gcc_9"]
+
+  artifacts:
+    paths:
+      - build/
+      - dist/
+
+  script:
+    - python3 setup.py bdist_wheel
+
+###############################################################################
+
 clang_10:
   extends: .gnu_build_template
 
@@ -173,7 +173,7 @@ build_singularity_image:
       - Containers/VirtualFluidsOpenMPI.sif
 
   script:
-    - singularity build Containers/VirtualFluidsOpenMPI.sif Containers/VirtualFluidsOpenMPI.def
+    - singularity build --fakeroot Containers/VirtualFluidsOpenMPI.sif Containers/VirtualFluidsOpenMPI.def
     - ls -sh Containers/VirtualFluidsOpenMPI.sif
 
 ###############################################################################
diff --git a/Python/poiseuille/test_poiseuille_l2.py b/Python/poiseuille/test_poiseuille_l2.py
index 852d458f468caa7186184cd416794758d4aa2c67..700209925b15743a9937a825f80ed19d921b7110 100644
--- a/Python/poiseuille/test_poiseuille_l2.py
+++ b/Python/poiseuille/test_poiseuille_l2.py
@@ -30,13 +30,15 @@ class TestPoiseuilleFlow(unittest.TestCase):
         grid_params = create_grid_params_with_nodes_in_column(nodes_in_column=5, height=10)
         l2_norm_result_100 = get_l2_norm_for_simulation(grid_params, physical_params, runtime_params, 11)
 
-        runtime_params.number_of_timesteps = 20000
+        runtime_params.number_of_timesteps *= 2
+        physical_params.lattice_viscosity *= 2
         grid_params = create_grid_params_with_nodes_in_column(nodes_in_column=10, height=10)
         l2_norm_result_200 = get_l2_norm_for_simulation(grid_params, physical_params, runtime_params, 11)
 
-        # runtime_params.number_of_timesteps = 40000
-        # grid_params = create_grid_params_with_nodes_in_column(nodes_in_column=20, height=10)
-        # l2_norm_result_400 = get_l2_norm_for_simulation(grid_params, physical_params, runtime_params, 11)
+        runtime_params.number_of_timesteps *= 2
+        physical_params.lattice_viscosity *= 2
+        grid_params = create_grid_params_with_nodes_in_column(nodes_in_column=20, height=10)
+        l2_norm_result_400 = get_l2_norm_for_simulation(grid_params, physical_params, runtime_params, 11)
 
         # nodes = [5, 10, 20]
         # l2_norms = [l2_norm_result_100, l2_norm_result_200, l2_norm_result_400]
diff --git a/src/cpu/simulationconfig/src/Simulation.cpp b/src/cpu/simulationconfig/src/Simulation.cpp
index 049fcb21c2030bf13d9fcaec3385cb0bbb925e30..5af7d5cf995d1ca279ad4564ff96d7aaf1c21f62 100644
--- a/src/cpu/simulationconfig/src/Simulation.cpp
+++ b/src/cpu/simulationconfig/src/Simulation.cpp
@@ -133,10 +133,9 @@ void Simulation::run()
     grid->accept(kernelVisitor);
     intHelper.setBC();
 
+    double bulkViscosity = physicalParameters->latticeViscosity * physicalParameters->bulkViscosityFactor;
     auto iProcessor = std::make_shared<CompressibleOffsetMomentsInterpolationProcessor>();
-    dynamicPointerCast<CompressibleOffsetMomentsInterpolationProcessor>(iProcessor)->setBulkViscosity(
-            physicalParameters->latticeViscosity,
-            physicalParameters->latticeViscosity * physicalParameters->bulkViscosityFactor);
+    iProcessor->setBulkViscosity(physicalParameters->latticeViscosity, bulkViscosity);
 
     SetConnectorsBlockVisitor setConnsVisitor(communicator, true,
                                               lbmSystem->getNumberOfDirections(),