diff --git a/hapi-fhir-jpaserver-base/src/main/java/ca/uhn/fhir/jpa/subscription/BaseSubscriptionInterceptor.java b/hapi-fhir-jpaserver-base/src/main/java/ca/uhn/fhir/jpa/subscription/BaseSubscriptionInterceptor.java
index 2d060c56575..8145dff30d1 100644
--- a/hapi-fhir-jpaserver-base/src/main/java/ca/uhn/fhir/jpa/subscription/BaseSubscriptionInterceptor.java
+++ b/hapi-fhir-jpaserver-base/src/main/java/ca/uhn/fhir/jpa/subscription/BaseSubscriptionInterceptor.java
@@ -478,6 +478,8 @@ public abstract class BaseSubscriptionInterceptor<S extends IBaseResource> exten
 			TransactionSynchronizationManager.registerSynchronization(new TransactionSynchronizationAdapter() {
 				@Override
 				public void afterCommit() {
+					// FIXME: remove
+					ourLog.info("** Sending processing message " + theMessage + " for: " + theMessage.getNewPayload(myCtx));
 					ourLog.trace("Sending resource modified message to processing channel");
 					getProcessingChannel().send(new ResourceModifiedJsonMessage(theMessage));
 				}
diff --git a/hapi-fhir-jpaserver-base/src/main/java/ca/uhn/fhir/jpa/subscription/CanonicalSubscription.java b/hapi-fhir-jpaserver-base/src/main/java/ca/uhn/fhir/jpa/subscription/CanonicalSubscription.java
index 75b4126b4b7..d1c561db64c 100644
--- a/hapi-fhir-jpaserver-base/src/main/java/ca/uhn/fhir/jpa/subscription/CanonicalSubscription.java
+++ b/hapi-fhir-jpaserver-base/src/main/java/ca/uhn/fhir/jpa/subscription/CanonicalSubscription.java
@@ -132,7 +132,7 @@ public class CanonicalSubscription implements Serializable {
 		return retVal;
 	}
 
-	String getIdElementString() {
+	public String getIdElementString() {
 		return myIdElement;
 	}
 
diff --git a/hapi-fhir-jpaserver-base/src/main/java/ca/uhn/fhir/jpa/subscription/ResourceDeliveryMessage.java b/hapi-fhir-jpaserver-base/src/main/java/ca/uhn/fhir/jpa/subscription/ResourceDeliveryMessage.java
index f7f7c8d374c..ca1ffa7ad7d 100644
--- a/hapi-fhir-jpaserver-base/src/main/java/ca/uhn/fhir/jpa/subscription/ResourceDeliveryMessage.java
+++ b/hapi-fhir-jpaserver-base/src/main/java/ca/uhn/fhir/jpa/subscription/ResourceDeliveryMessage.java
@@ -48,6 +48,13 @@ public class ResourceDeliveryMessage {
 		return myOperationType;
 	}
 
+	/**
+	 * Constructor
+	 */
+	public ResourceDeliveryMessage() {
+		super();
+	}
+
 	public void setOperationType(ResourceModifiedMessage.OperationTypeEnum theOperationType) {
 		myOperationType = theOperationType;
 	}
diff --git a/hapi-fhir-jpaserver-base/src/main/java/ca/uhn/fhir/jpa/subscription/SubscriptionActivatingSubscriber.java b/hapi-fhir-jpaserver-base/src/main/java/ca/uhn/fhir/jpa/subscription/SubscriptionActivatingSubscriber.java
index 7b80f1dfef8..209f5cb23bc 100644
--- a/hapi-fhir-jpaserver-base/src/main/java/ca/uhn/fhir/jpa/subscription/SubscriptionActivatingSubscriber.java
+++ b/hapi-fhir-jpaserver-base/src/main/java/ca/uhn/fhir/jpa/subscription/SubscriptionActivatingSubscriber.java
@@ -69,7 +69,7 @@ public class SubscriptionActivatingSubscriber {
 		Validate.notNull(theTaskExecutor);
 	}
 
-	public synchronized boolean activateOrRegisterSubscriptionIfRequired(final IBaseResource theSubscription) {
+	public boolean activateOrRegisterSubscriptionIfRequired(final IBaseResource theSubscription) {
 		// Grab the value for "Subscription.channel.type" so we can see if this
 		// subscriber applies..
 		String subscriptionChannelType = myCtx
@@ -180,7 +180,7 @@ public class SubscriptionActivatingSubscriber {
 
 	}
 
-	private synchronized void activateAndRegisterSubscriptionIfRequiredInTransaction(IBaseResource theSubscription) {
+	private void activateAndRegisterSubscriptionIfRequiredInTransaction(IBaseResource theSubscription) {
 		TransactionTemplate txTemplate = new TransactionTemplate(myTransactionManager);
 		txTemplate.execute(new TransactionCallbackWithoutResult() {
 			@Override
@@ -190,7 +190,7 @@ public class SubscriptionActivatingSubscriber {
 		});
 	}
 
-	protected boolean registerSubscriptionUnlessAlreadyRegistered(IBaseResource theSubscription) {
+	protected synchronized boolean registerSubscriptionUnlessAlreadyRegistered(IBaseResource theSubscription) {
 		CanonicalSubscription existingSubscription = mySubscriptionInterceptor.hasSubscription(theSubscription.getIdElement());
 		CanonicalSubscription newSubscription = mySubscriptionInterceptor.canonicalize(theSubscription);
 
diff --git a/hapi-fhir-jpaserver-base/src/main/java/ca/uhn/fhir/jpa/subscription/resthook/SubscriptionDeliveringRestHookSubscriber.java b/hapi-fhir-jpaserver-base/src/main/java/ca/uhn/fhir/jpa/subscription/resthook/SubscriptionDeliveringRestHookSubscriber.java
index 37ed373598c..4a1cbd8167a 100644
--- a/hapi-fhir-jpaserver-base/src/main/java/ca/uhn/fhir/jpa/subscription/resthook/SubscriptionDeliveringRestHookSubscriber.java
+++ b/hapi-fhir-jpaserver-base/src/main/java/ca/uhn/fhir/jpa/subscription/resthook/SubscriptionDeliveringRestHookSubscriber.java
@@ -108,6 +108,10 @@ public class SubscriptionDeliveringRestHookSubscriber extends BaseSubscriptionDe
 			operation.encoded(thePayloadType);
 		}
 
+		// FIXME: remove
+		ourLog.info("** This " + this + " Processing delivery message " + theMsg);
+
+
 		ourLog.info("Delivering {} rest-hook payload {} for {}", theMsg.getOperationType(), thePayloadResource.getIdElement().toUnqualified().getValue(), theSubscription.getIdElement(getContext()).toUnqualifiedVersionless().getValue());
 
 		try {
diff --git a/hapi-fhir-jpaserver-base/src/main/java/ca/uhn/fhir/jpa/subscription/resthook/SubscriptionRestHookInterceptor.java b/hapi-fhir-jpaserver-base/src/main/java/ca/uhn/fhir/jpa/subscription/resthook/SubscriptionRestHookInterceptor.java
index 83ff6a3257d..17f597d548b 100644
--- a/hapi-fhir-jpaserver-base/src/main/java/ca/uhn/fhir/jpa/subscription/resthook/SubscriptionRestHookInterceptor.java
+++ b/hapi-fhir-jpaserver-base/src/main/java/ca/uhn/fhir/jpa/subscription/resthook/SubscriptionRestHookInterceptor.java
@@ -22,15 +22,21 @@ package ca.uhn.fhir.jpa.subscription.resthook;
 
 import ca.uhn.fhir.jpa.subscription.BaseSubscriptionInterceptor;
 import ca.uhn.fhir.jpa.subscription.CanonicalSubscription;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
 import org.springframework.messaging.MessageHandler;
 
 import java.util.Optional;
 
 public class SubscriptionRestHookInterceptor extends BaseSubscriptionInterceptor {
+	private static final Logger ourLog = LoggerFactory.getLogger(SubscriptionRestHookInterceptor.class);
 
 	@Override
 	protected Optional<MessageHandler> createDeliveryHandler(CanonicalSubscription theSubscription) {
-		return Optional.of(new SubscriptionDeliveringRestHookSubscriber(getSubscriptionDao(), getChannelType(), this));
+		SubscriptionDeliveringRestHookSubscriber value = new SubscriptionDeliveringRestHookSubscriber(getSubscriptionDao(), getChannelType(), this);
+		// FIXME: remove
+		ourLog.info("** Creating delivery subscriber " + value + " for " + theSubscription.getIdElementString());
+		return Optional.of(value);
 	}
 
 	@Override
diff --git a/hapi-fhir-jpaserver-base/src/test/java/ca/uhn/fhir/jpa/config/TestR4Config.java b/hapi-fhir-jpaserver-base/src/test/java/ca/uhn/fhir/jpa/config/TestR4Config.java
index ce3510616d8..89b114a0724 100644
--- a/hapi-fhir-jpaserver-base/src/test/java/ca/uhn/fhir/jpa/config/TestR4Config.java
+++ b/hapi-fhir-jpaserver-base/src/test/java/ca/uhn/fhir/jpa/config/TestR4Config.java
@@ -38,6 +38,7 @@ public class TestR4Config extends BaseJavaConfigR4 {
 		 * starvation
 		 */
 		ourMaxThreads = (int) (Math.random() * 6.0) + 1;
+		ourMaxThreads = 1;
 	}
 
 	private Exception myLastStackTrace;