diff --git a/src/main/java/com/amazonaws/services/kinesis/clientlibrary/proxies/KinesisProxy.java b/src/main/java/com/amazonaws/services/kinesis/clientlibrary/proxies/KinesisProxy.java
index 4ad2c508..073c1d19 100644
--- a/src/main/java/com/amazonaws/services/kinesis/clientlibrary/proxies/KinesisProxy.java
+++ b/src/main/java/com/amazonaws/services/kinesis/clientlibrary/proxies/KinesisProxy.java
@@ -30,6 +30,7 @@ import java.util.concurrent.atomic.AtomicInteger;
 import java.util.function.Function;
 import java.util.stream.Collectors;
 
+import com.amazonaws.services.kinesis.clientlibrary.utils.RequestUtil;
 import com.amazonaws.services.kinesis.model.ShardFilter;
 import com.amazonaws.util.CollectionUtils;
 import org.apache.commons.lang3.StringUtils;
@@ -60,7 +61,6 @@ import com.amazonaws.services.kinesis.model.ShardIteratorType;
 import com.amazonaws.services.kinesis.model.StreamStatus;
 
 import lombok.AccessLevel;
-import lombok.Data;
 import lombok.Getter;
 import lombok.Setter;
 
@@ -442,7 +442,7 @@ public class KinesisProxy implements IKinesisProxyExtended {
     @Override
     public synchronized List<Shard> getShardListWithFilter(ShardFilter shardFilter) {
         final List<Shard> shards = new ArrayList<>();
-
+        final List<String> requestIds = new ArrayList<>();
         if (isKinesisClient) {
             ListShardsResult result;
             String nextToken = null;
@@ -458,6 +458,7 @@ public class KinesisProxy implements IKinesisProxyExtended {
                     return null;
                 } else {
                     shards.addAll(result.getShards());
+                    requestIds.add(RequestUtil.requestId(result));
                     nextToken = result.getNextToken();
                 }
             } while (StringUtils.isNotEmpty(result.getNextToken()));
@@ -478,6 +479,7 @@ public class KinesisProxy implements IKinesisProxyExtended {
                 } else {
                     final List<Shard> pageOfShards = response.getStreamDescription().getShards();
                     shards.addAll(pageOfShards);
+                    requestIds.add(RequestUtil.requestId(response));
 
                     final Shard lastShard = pageOfShards.get(pageOfShards.size() - 1);
                     if (lastShardId == null || lastShardId.compareTo(lastShard.getShardId()) < 0) {
@@ -487,6 +489,9 @@ public class KinesisProxy implements IKinesisProxyExtended {
             } while (response.getStreamDescription().isHasMoreShards());
         }
         final List<Shard> dedupedShards = new ArrayList<>(new LinkedHashSet<>(shards));
+        if (dedupedShards.size() < shards.size()) {
+            LOG.warn("Found duplicate child shards in ListShards response. Request ids - " + requestIds);
+        }
         this.cachedShardMap = dedupedShards.stream().collect(Collectors.toMap(Shard::getShardId, Function.identity()));
         this.lastCacheUpdateTime = Instant.now();
 
diff --git a/src/main/java/com/amazonaws/services/kinesis/clientlibrary/utils/RequestUtil.java b/src/main/java/com/amazonaws/services/kinesis/clientlibrary/utils/RequestUtil.java
new file mode 100644
index 00000000..cac65d45
--- /dev/null
+++ b/src/main/java/com/amazonaws/services/kinesis/clientlibrary/utils/RequestUtil.java
@@ -0,0 +1,24 @@
+package com.amazonaws.services.kinesis.clientlibrary.utils;
+
+import com.amazonaws.AmazonWebServiceResult;
+
+/**
+ * Helper class to parse metadata from AWS requests.
+ */
+public class RequestUtil {
+    private static final String DEFAULT_REQUEST_ID = "NONE";
+
+    /**
+     * Get the requestId associated with a request.
+     *
+     * @param result
+     * @return the requestId for a request, or "NONE" if one is not available.
+     */
+    public static String requestId(AmazonWebServiceResult result) {
+        if (result == null || result.getSdkResponseMetadata() == null || result.getSdkResponseMetadata().getRequestId() == null) {
+            return DEFAULT_REQUEST_ID;
+        }
+
+        return result.getSdkResponseMetadata().getRequestId();
+    }
+}
diff --git a/src/test/java/com/amazonaws/services/kinesis/clientlibrary/proxies/KinesisProxyTest.java b/src/test/java/com/amazonaws/services/kinesis/clientlibrary/proxies/KinesisProxyTest.java
index 553d451a..76671176 100644
--- a/src/test/java/com/amazonaws/services/kinesis/clientlibrary/proxies/KinesisProxyTest.java
+++ b/src/test/java/com/amazonaws/services/kinesis/clientlibrary/proxies/KinesisProxyTest.java
@@ -24,6 +24,7 @@ import static org.hamcrest.Matchers.nullValue;
 import static org.junit.Assert.assertEquals;
 import static org.junit.Assert.assertNull;
 import static org.junit.Assert.assertThat;
+import static org.junit.Assert.fail;
 import static org.mockito.Matchers.any;
 import static org.mockito.Matchers.argThat;
 import static org.mockito.Mockito.doReturn;
@@ -92,6 +93,7 @@ public class KinesisProxyTest {
     private static final String SHARD_4 = "shard-4";
     private static final String NOT_CACHED_SHARD = "ShardId-0005";
     private static final String NEVER_PRESENT_SHARD = "ShardId-0010";
+    private static final String REQUEST_ID = "requestId";
 
     @Mock
     private AmazonKinesis mockClient;
@@ -435,26 +437,41 @@ public class KinesisProxyTest {
         verify(mockClient).listShards(any());
     }
 
+    /**
+     * Tests that if we fail halfway through a listShards call, we fail gracefully and subsequent calls are not
+     * affected by the failure of the first request.
+     */
     @Test
     public void testNoDuplicateShardsInPartialFailure() {
         proxy.setCachedShardMap(null);
+
         ListShardsResult firstPage = new ListShardsResult().withShards(shards.subList(0, 2)).withNextToken(NEXT_TOKEN);
         ListShardsResult lastPage = new ListShardsResult().withShards(shards.subList(2, shards.size())).withNextToken(null);
-        when(mockClient.listShards(any())).thenReturn(firstPage).thenThrow(new RuntimeException("Failed!")) // First call
-                .thenReturn(firstPage).thenReturn(lastPage); // second call
+
+        when(mockClient.listShards(any()))
+                .thenReturn(firstPage).thenThrow(new RuntimeException("Failed!"))
+                .thenReturn(firstPage).thenReturn(lastPage);
 
         try {
             proxy.getShardList();
+            fail("First ListShards call should have failed!");
         } catch (Exception e) {
             // Do nothing
         }
         assertEquals(shards, proxy.getShardList());
     }
 
+    /**
+     * Tests that if we receive any duplicate shard responses from the service during a shard sync, we dedup the response
+     * and continue gracefully.
+     */
     @Test
     public void testDuplicateShardResponseDedupedGracefully() {
         proxy.setCachedShardMap(null);
-        ListShardsResult pageOfShards = new ListShardsResult().withShards(shards).withNextToken(null);
+        List<Shard> duplicateShards = new ArrayList<>(shards);
+        duplicateShards.addAll(shards);
+        ListShardsResult pageOfShards = new ListShardsResult().withShards(duplicateShards).withNextToken(null);
+
         when(mockClient.listShards(any())).thenReturn(pageOfShards);
 
         proxy.getShardList();