diff --git a/Event/xAOD/xAODTruthAthenaPool/src/xAODTruthParticleAuxContainerCnv_v1.cxx b/Event/xAOD/xAODTruthAthenaPool/src/xAODTruthParticleAuxContainerCnv_v1.cxx
index 607d78c2f812d2b5a173fc5b9dd082dc2f8aa590..5631a27bdf5d233569473f197c2ec9312086e39d 100644
--- a/Event/xAOD/xAODTruthAthenaPool/src/xAODTruthParticleAuxContainerCnv_v1.cxx
+++ b/Event/xAOD/xAODTruthAthenaPool/src/xAODTruthParticleAuxContainerCnv_v1.cxx
@@ -61,6 +61,7 @@ void xAODTruthParticleAuxContainerCnv_v1::persToTrans(
     // This should be fine in the case that we are not mixing use of
     // xAOD::Truth with containers linking to HepMC Truth in the same
     // classes.
+    ++index;
   }
   return;
 }
diff --git a/Event/xAOD/xAODTruthAthenaPool/src/xAODTruthVertexAuxContainerCnv_v1.cxx b/Event/xAOD/xAODTruthAthenaPool/src/xAODTruthVertexAuxContainerCnv_v1.cxx
index 7af2eaeee7d43df8b9d20cb27edd39bb79432ddc..1c424b238b2d4f52eca4b6268593a390c72bd459 100644
--- a/Event/xAOD/xAODTruthAthenaPool/src/xAODTruthVertexAuxContainerCnv_v1.cxx
+++ b/Event/xAOD/xAODTruthAthenaPool/src/xAODTruthVertexAuxContainerCnv_v1.cxx
@@ -63,6 +63,7 @@ void xAODTruthVertexAuxContainerCnv_v1::persToTrans(
     // This should be fine in the case that we are not mixing use of
     // xAOD::Truth with containers linking to HepMC Truth in the same
     // classes.
+    ++index;
   }
   return;
 }