diff --git a/jetty-http2/http2-common/src/main/java/org/eclipse/jetty/http2/parser/HeaderBlockParser.java b/jetty-http2/http2-common/src/main/java/org/eclipse/jetty/http2/parser/HeaderBlockParser.java
index e66888fb92b..855e0899086 100644
--- a/jetty-http2/http2-common/src/main/java/org/eclipse/jetty/http2/parser/HeaderBlockParser.java
+++ b/jetty-http2/http2-common/src/main/java/org/eclipse/jetty/http2/parser/HeaderBlockParser.java
@@ -75,7 +75,12 @@ public class HeaderBlockParser
             MetaData result = hpackDecoder.decode(toDecode);
 
             buffer.limit(limit);
-            byteBufferPool.release(blockBuffer);
+
+            if (blockBuffer != null)
+            {
+                byteBufferPool.release(blockBuffer);
+                blockBuffer = null;
+            }
 
             return result;
         }
diff --git a/jetty-http2/http2-common/src/test/java/org/eclipse/jetty/http2/frames/HeadersGenerateParseTest.java b/jetty-http2/http2-common/src/test/java/org/eclipse/jetty/http2/frames/HeadersGenerateParseTest.java
index a7796f0a32f..25bb969f4de 100644
--- a/jetty-http2/http2-common/src/test/java/org/eclipse/jetty/http2/frames/HeadersGenerateParseTest.java
+++ b/jetty-http2/http2-common/src/test/java/org/eclipse/jetty/http2/frames/HeadersGenerateParseTest.java
@@ -114,41 +114,47 @@ public class HeadersGenerateParseTest
             }
         }, 4096, 8192);
 
-        int streamId = 13;
-        HttpFields fields = new HttpFields();
-        fields.put("Accept", "text/html");
-        fields.put("User-Agent", "Jetty");
-        MetaData.Request metaData = new MetaData.Request("GET", HttpScheme.HTTP, new HostPortHttpField("localhost:8080"), "/path", HttpVersion.HTTP_2, fields);
-
-        ByteBufferPool.Lease lease = new ByteBufferPool.Lease(byteBufferPool);
-        PriorityFrame priorityFrame = new PriorityFrame(streamId, 3 * streamId, 200, true);
-        generator.generateHeaders(lease, streamId, metaData, priorityFrame, true);
-
-        for (ByteBuffer buffer : lease.getByteBuffers())
+        // Iterate a few times to be sure generator and parser are properly reset.
+        for (int i = 0; i < 2; ++i)
         {
-            while (buffer.hasRemaining())
+            int streamId = 13;
+            HttpFields fields = new HttpFields();
+            fields.put("Accept", "text/html");
+            fields.put("User-Agent", "Jetty");
+            MetaData.Request metaData = new MetaData.Request("GET", HttpScheme.HTTP, new HostPortHttpField("localhost:8080"), "/path", HttpVersion.HTTP_2, fields);
+
+            ByteBufferPool.Lease lease = new ByteBufferPool.Lease(byteBufferPool);
+            PriorityFrame priorityFrame = new PriorityFrame(streamId, 3 * streamId, 200, true);
+            generator.generateHeaders(lease, streamId, metaData, priorityFrame, true);
+
+            frames.clear();
+            for (ByteBuffer buffer : lease.getByteBuffers())
             {
-                parser.parse(ByteBuffer.wrap(new byte[]{buffer.get()}));
+                buffer = buffer.slice();
+                while (buffer.hasRemaining())
+                {
+                    parser.parse(ByteBuffer.wrap(new byte[]{buffer.get()}));
+                }
             }
-        }
 
-        Assert.assertEquals(1, frames.size());
-        HeadersFrame frame = frames.get(0);
-        Assert.assertEquals(streamId, frame.getStreamId());
-        Assert.assertTrue(frame.isEndStream());
-        MetaData.Request request = (MetaData.Request)frame.getMetaData();
-        Assert.assertEquals(metaData.getMethod(), request.getMethod());
-        Assert.assertEquals(metaData.getURI(), request.getURI());
-        for (int j = 0; j < fields.size(); ++j)
-        {
-            HttpField field = fields.getField(j);
-            Assert.assertTrue(request.getFields().contains(field));
+            Assert.assertEquals(1, frames.size());
+            HeadersFrame frame = frames.get(0);
+            Assert.assertEquals(streamId, frame.getStreamId());
+            Assert.assertTrue(frame.isEndStream());
+            MetaData.Request request = (MetaData.Request)frame.getMetaData();
+            Assert.assertEquals(metaData.getMethod(), request.getMethod());
+            Assert.assertEquals(metaData.getURI(), request.getURI());
+            for (int j = 0; j < fields.size(); ++j)
+            {
+                HttpField field = fields.getField(j);
+                Assert.assertTrue(request.getFields().contains(field));
+            }
+            PriorityFrame priority = frame.getPriority();
+            Assert.assertNotNull(priority);
+            Assert.assertEquals(priorityFrame.getStreamId(), priority.getStreamId());
+            Assert.assertEquals(priorityFrame.getParentStreamId(), priority.getParentStreamId());
+            Assert.assertEquals(priorityFrame.getWeight(), priority.getWeight());
+            Assert.assertEquals(priorityFrame.isExclusive(), priority.isExclusive());
         }
-        PriorityFrame priority = frame.getPriority();
-        Assert.assertNotNull(priority);
-        Assert.assertEquals(priorityFrame.getStreamId(), priority.getStreamId());
-        Assert.assertEquals(priorityFrame.getParentStreamId(), priority.getParentStreamId());
-        Assert.assertEquals(priorityFrame.getWeight(), priority.getWeight());
-        Assert.assertEquals(priorityFrame.isExclusive(), priority.isExclusive());
     }
 }