diff --git a/DDTest/CMakeLists.txt b/DDTest/CMakeLists.txt
index 8b2f414b0d36bbf48c90ea22ebfd259a1a12be02..45fd6b89670ab87f471d52d6b65b13d782fd8083 100644
--- a/DDTest/CMakeLists.txt
+++ b/DDTest/CMakeLists.txt
@@ -56,12 +56,14 @@ if (DD4HEP_USE_GEANT4)
   ADD_TEST( t_test_python_import_ddg4 "${CMAKE_INSTALL_PREFIX}/bin/run_test.sh"
     pytest ${PROJECT_SOURCE_DIR}/DDTest/python/test_import_ddg4.py)
   SET_TESTS_PROPERTIES( t_test_python_import_ddg4 PROPERTIES FAIL_REGULAR_EXPRESSION  "Exception;EXCEPTION;ERROR;Error" )
+
   if(DD4HEP_USE_HEPMC3)
     ADD_TEST( t_test_ddsim_ion_hepmc3 "${CMAKE_INSTALL_PREFIX}/bin/run_test.sh"
       ddsim --compactFile=${CMAKE_INSTALL_PREFIX}/DDDetectors/compact/SiD.xml --runType=batch -N=2
       --outputFile=testSidIons.root --inputFiles ${CMAKE_CURRENT_SOURCE_DIR}/inputFiles/Pythia_output.hepmc
       --part.userParticleHandler=)
-    SET_TESTS_PROPERTIES( t_test_ddsim_ion_hepmc3 PROPERTIES FAIL_REGULAR_EXPRESSION  "Exception;EXCEPTION;ERROR;Error" )
+    # Tests causes G4Exception about: Isomer level 9 may be ambiguous, just a warning
+    SET_TESTS_PROPERTIES( t_test_ddsim_ion_hepmc3 PROPERTIES FAIL_REGULAR_EXPRESSION  "ERROR;Error" )
   endif()
 
   foreach(TEST_NAME