diff --git a/src/storm-cli-utilities/model-handling.h b/src/storm-cli-utilities/model-handling.h
index 6dad6fbb0..e6508c190 100644
--- a/src/storm-cli-utilities/model-handling.h
+++ b/src/storm-cli-utilities/model-handling.h
@@ -566,6 +566,10 @@ namespace storm {
             if (ioSettings.isExportExplicitSet()) {
                 storm::api::exportSparseModelAsDrn(model, ioSettings.getExportExplicitFilename(), input.model ? input.model.get().getParameterNames() : std::vector<std::string>());
             }
+
+            if (ioSettings.isExportDdSet()) {
+                STORM_LOG_THROW(false, storm::exceptions::NotSupportedException, "Exporting in drdd format is only supported for DDs.");
+            }
             
             if (ioSettings.isExportDotSet()) {
                 storm::api::exportSparseModelAsDot(model, ioSettings.getExportDotFilename(), ioSettings.getExportDotMaxWidth());
@@ -576,6 +580,10 @@ namespace storm {
         void exportDdModel(std::shared_ptr<storm::models::symbolic::Model<DdType, ValueType>> const& model, SymbolicInput const& input) {
             auto ioSettings = storm::settings::getModule<storm::settings::modules::IOSettings>();
 
+            if (ioSettings.isExportExplicitSet()) {
+                STORM_LOG_THROW(false, storm::exceptions::NotSupportedException, "Exporting in drn format is only supported for sparse models.");
+            }
+
             if (ioSettings.isExportDdSet()) {
                 storm::api::exportSparseModelAsDrdd(model, ioSettings.getExportDdFilename());
             }
diff --git a/src/storm/storage/memorystructure/SparseModelMemoryProduct.cpp b/src/storm/storage/memorystructure/SparseModelMemoryProduct.cpp
index 3907f0625..1f30f23fb 100644
--- a/src/storm/storage/memorystructure/SparseModelMemoryProduct.cpp
+++ b/src/storm/storage/memorystructure/SparseModelMemoryProduct.cpp
@@ -410,7 +410,7 @@ namespace storm {
                                 if (isStateReachable(modelState, memoryState)) {
                                     if (scheduler && scheduler->getChoice(modelState, memoryState).isDefined()) {
                                         ValueType factor = scheduler->getChoice(modelState, memoryState).getChoiceAsDistribution().getProbability(rowOffset);
-                                        stateActionRewards.get()[resultTransitionMatrix.getRowGroupIndices()[getResultState(modelState, memoryState)]] = factor * modelStateActionReward;
+                                        stateActionRewards.get()[resultTransitionMatrix.getRowGroupIndices()[getResultState(modelState, memoryState)]] += factor * modelStateActionReward;
                                     } else {
                                         stateActionRewards.get()[resultTransitionMatrix.getRowGroupIndices()[getResultState(modelState, memoryState)] + rowOffset] = modelStateActionReward;
                                     }