diff --git a/openjpa-persistence/src/main/java/org/apache/openjpa/persistence/EntityManagerFactoryImpl.java b/openjpa-persistence/src/main/java/org/apache/openjpa/persistence/EntityManagerFactoryImpl.java
index 0c8ff9aec..ff06de691 100644
--- a/openjpa-persistence/src/main/java/org/apache/openjpa/persistence/EntityManagerFactoryImpl.java
+++ b/openjpa-persistence/src/main/java/org/apache/openjpa/persistence/EntityManagerFactoryImpl.java
@@ -281,9 +281,11 @@ public class EntityManagerFactoryImpl
         OpenJPAEntityManagerSPI em = newEntityManagerImpl(broker);
 
         // allow setting of other bean properties of EM
-        Set<Map.Entry> entrySet = props.entrySet();
-        for (Map.Entry entry : entrySet) {
-            em.setProperty(entry.getKey().toString(), entry.getValue());
+        if (!props.isEmpty()) {
+            Set<Map.Entry> entrySet = props.entrySet();
+            for (Map.Entry entry : entrySet) {
+                em.setProperty(entry.getKey().toString(), entry.getValue());
+            }
         }
         if (canCacheGetProperties) {
             if (emEmptyPropsProperties == null) {
diff --git a/openjpa-persistence/src/main/java/org/apache/openjpa/persistence/EntityManagerImpl.java b/openjpa-persistence/src/main/java/org/apache/openjpa/persistence/EntityManagerImpl.java
index 978241230..1a171ddc5 100644
--- a/openjpa-persistence/src/main/java/org/apache/openjpa/persistence/EntityManagerImpl.java
+++ b/openjpa-persistence/src/main/java/org/apache/openjpa/persistence/EntityManagerImpl.java
@@ -2121,6 +2121,7 @@ public class EntityManagerImpl
      */
     @Override
     public void setProperty(String prop, Object value) {
+        properties = null;
         if (!setKernelProperty(this, prop, value)) {
             if (!setKernelProperty(this.getFetchPlan(), prop, value)) {
                 Log log = getConfiguration().getLog(OpenJPAConfiguration.LOG_RUNTIME);