ActiveMQ doesn't propagate topics on failover reconnection - activemq

Question

I'm attempting to use a network of brokers that bridges two LANs over a duplex WAN connector:
There are actually many subscribers in our setup, each connecting to a different "Broker A", if that makes sense. All of the Broker A instances have their own connections to a single "Broker B".
Software and configurations:
ActiveMQ 5.14.0, Java 8
All brokers have non-persistent topics only; advisory messages are on.
OS: Linux (RHEL 6)
When I initially bring everything online, regardless of the order in which I bring things online, communication between the publisher and subscriber works flawlessly. I've had the system up-and-running for weeks at a time without issue.
What I've observed is that if broker C is restarted, no new topics that show up in broker B ever appear in broker C. New topics are still appearing in broker B as they are created by the subscriber(s). Neither existing nor new topics ever propagate across the WAN to broker C. I've verified this using jconsole.
If I restart broker B, the problem goes away immediately. The topics contained in broker B (according to jconsole) are the same as they were prior to restart, but now they've magically appeared in C.
Brokers B and C have the same configuration (shown below). The only difference is that B creates a duplex network connector to C created using the following code:
final NetworkConnector wanNC = new DiscoveryNetworkConnector(
new URI(String.format("static:(failover:(tcp://%s:%d))", parentNode, port)));
wanNC.setCheckDuplicateMessagesOnDuplex(true);
wanNC.setDecreaseNetworkConsumerPriority(true);
wanNC.setDuplex(true);
wanNC.setName(NetworkUtils.getHostName());
wanNC.setNetworkTTL(10);
wanNC.setSuppressDuplicateTopicSubscriptions(false);
broker.addNetworkConnector(wanNC);
broker.xml:
<beans xmlns="http://www.springframework.org/schema/beans" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd
http://activemq.apache.org/schema/core http://activemq.apache.org/schema/core/activemq-core.xsd">
<!-- Allows us to use system properties as variables in this configuration file -->
<bean class="org.springframework.beans.factory.config.PropertyPlaceholderConfigurer" />
<broker xmlns="http://activemq.apache.org/schema/core" brokerName="${broker.id}" start="false"
offlineDurableSubscriberTimeout="5000" offlineDurableSubscriberTaskSchedule="5000"
persistent="false" useJmx="true" schedulePeriodForDestinationPurge="86400000">
[...]
<networkConnectors>
<networkConnector name="z-broker-${broker.id}-x-nc"
decreaseNetworkConsumerPriority="true"
networkTTL="10"
uri="multicast://225.5.5.5:6555?group=TO_X">
<excludedDestinations>
<topic physicalName="X.A" />
</excludedDestinations>
</networkConnector>
<networkConnector name="z-broker-${broker.id}-y-nc"
decreaseNetworkConsumerPriority="true"
networkTTL="10"
uri="multicast://225.5.5.5:6555?group=TO_Y">
<excludedDestinations>
<topic physicalName="X.B.>" />
</excludedDestinations>
</networkConnector>
</networkConnectors>
<transportConnectors>
<transportConnector name="openwire"
uri="tcp://${broker.ip}:${broker.port}?maximumConnections=1000&wireFormat.maxFrameSize=104857600"
discoveryUri="multicast://225.5.5.5:6555?group=TO_Z" />
</transportConnectors>
</broker>
</beans>
Why don't topics from broker B (existing or new) ever show up in broker C?
Why does restarting broker B solve the issue immediately?

Answer 1

Apparently the trick was changing the network connector URI from
static:(failover:(tcp://<ip>:<port>))
to
static:(tcp://<ip>:<port>)
I didn't need failover transport for any reason since the connection is intended as a network bridge and there's a single remote address.
For whatever reason, using failover prevented topics from propagating on reconnect.