diff --git a/DDTest/CMakeLists.txt b/DDTest/CMakeLists.txt
index 45fd6b89670ab87f471d52d6b65b13d782fd8083..9f6de1bf8da17c371453992fdff0863ab3d1d49b 100644
--- a/DDTest/CMakeLists.txt
+++ b/DDTest/CMakeLists.txt
@@ -59,11 +59,12 @@ if (DD4HEP_USE_GEANT4)
 
   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
+      ddsim --compactFile=${CMAKE_INSTALL_PREFIX}/DDDetectors/compact/SiD.xml --runType=batch -N=1
       --outputFile=testSidIons.root --inputFiles ${CMAKE_CURRENT_SOURCE_DIR}/inputFiles/Pythia_output.hepmc
       --part.userParticleHandler=)
     # 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" )
+    # space before Exception intentional!!!
+    SET_TESTS_PROPERTIES( t_test_ddsim_ion_hepmc3 PROPERTIES FAIL_REGULAR_EXPRESSION  "ERROR;Error; Exception" )
   endif()
 
   foreach(TEST_NAME
diff --git a/examples/DDDigi/CMakeLists.txt b/examples/DDDigi/CMakeLists.txt
index be6f07590e915cacc83997672bbeedb9f117bae4..67f78f81680613620d3eddf664231f98dcca3cf1 100644
--- a/examples/DDDigi/CMakeLists.txt
+++ b/examples/DDDigi/CMakeLists.txt
@@ -68,7 +68,8 @@ if (DD4HEP_USE_GEANT4)
     EXEC_ARGS  ${Python_EXECUTABLE} ${CMAKE_INSTALL_PREFIX}/examples/ClientTests/scripts/MiniTelGenerate.py
          -batch -events 30 -runs 8
     REGEX_PASS "\\+\\+\\+ Finished run 7 after 30 events \\(240 events in total\\)."
-    REGEX_FAIL "Error;ERROR;FATAL;Exception"
+    # Space is intentional to avoid G4Exception (From FindIon)
+    REGEX_FAIL "Error;ERROR;FATAL; Exception"
   )
   # Test basic input reading from DDG4
   dd4hep_add_test_reg(DDDigi_test_input_reading
@@ -225,7 +226,7 @@ if (DD4HEP_USE_GEANT4)
       -batch -events 30 -runs 3 -output MiniTel_DDG4_edm4hep_data.root
       DEPENDS    DDDigi_generate_ddg4_data
       REGEX_PASS "\\+\\+\\+ Finished run 2 after 30 events \\(90 events in total\\)."
-      REGEX_FAIL "Error;ERROR;FATAL;Exception"
+      REGEX_FAIL "Error;ERROR;FATAL; Exception"
     )
     # Test reading EDM4HEP input written with DDG4
     dd4hep_add_test_reg(DDDigi_test_edm4hep_read
diff --git a/examples/OpticalTracker/CMakeLists.txt b/examples/OpticalTracker/CMakeLists.txt
index 504d5bc43cfa8c4c618f46ad94ca7ced0dde6bf4..9dffe3c6588128dced55857d021a9ec8179f5d2d 100644
--- a/examples/OpticalTracker/CMakeLists.txt
+++ b/examples/OpticalTracker/CMakeLists.txt
@@ -45,7 +45,7 @@ dd4hep_add_test_reg( OpticalTracker_simulation
   EXEC_ARGS  ${Python_EXECUTABLE} ${OpticalTracker_INSTALL}/scripts/richsim.py
              --outputFile "${OpticalTracker_INSTALL}/sim.root"
   REGEX_PASS "TEST: passed"
-  REGEX_FAIL "Exception;EXCEPTION;ERROR;Error;FATAL"
+  REGEX_FAIL " Exception; EXCEPTION;ERROR;Error;FATAL"
   )
 
 # ---Test: Number of raw photon hits