diff --git a/apps/segmentrouting/src/main/java/org/onosproject/segmentrouting/NetworkConfigEventHandler.java b/apps/segmentrouting/src/main/java/org/onosproject/segmentrouting/NetworkConfigEventHandler.java
index 7e9dd55..0c3fac7 100644
--- a/apps/segmentrouting/src/main/java/org/onosproject/segmentrouting/NetworkConfigEventHandler.java
+++ b/apps/segmentrouting/src/main/java/org/onosproject/segmentrouting/NetworkConfigEventHandler.java
@@ -73,8 +73,8 @@
         SegmentRoutingAppConfig config = (SegmentRoutingAppConfig) event.config().get();
         SegmentRoutingAppConfig prevConfig = (SegmentRoutingAppConfig) event.prevConfig().get();
         deviceService.getAvailableDevices().forEach(device -> {
-            Set<MacAddress> macAddresses = getMacAddresses(config);
-            Set<MacAddress> prevMacAddresses = getMacAddresses(prevConfig);
+            Set<MacAddress> macAddresses = new HashSet<>(getMacAddresses(config));
+            Set<MacAddress> prevMacAddresses = new HashSet<>(getMacAddresses(prevConfig));
             // Avoid removing and re-adding unchanged MAC addresses since
             // FlowObjective does not guarantee the execution order.
             Set<MacAddress> sameMacAddresses = new HashSet<>(macAddresses);