Communicate between two plugins using MessageBus Follow

I've created two plugins and I'm trying to get them to communicate. The implementation I'm using is shown below. Plugin B still isn't receiving the message from Plugin A. What am I doing wrong? Or is there another way I can accomplish this?

Plugin A: com.plugina.analysis

MarkerNotifier is implemented this way.

public interface MarkerNotifier {

    Topic<MarkerNotifier> FILE_NOTIFIER_TOPIC = Topic.create("New Markers", MarkerNotifier.class);
    void loadNewMarkers();
}

This is how I send the update from the plugin.

MessageBus messageBus = activeProject.getMessageBus();
MarkerNotifier publisher = messageBus.syncPublisher(MarkerNotifier.FILE_NOTIFIER_TOPIC);
publisher.loadNewMarkers();

Plugin B: com.pluginb.viewer

Plugin B depends on Plugin A. 

<depends>com.plugina.analysis</depends>

The jars from Plugin A are placed the a libs folder in Plugin B.

compile fileTree(include: ['*.jar'], dir: 'libs')

I listen to the topic using the following code:

MessageBus bus = project.getMessageBus();
bus.connect().subscribe(MarkerNotifier.FILE_NOTIFIER_TOPIC, new MarkerNotifier() {
    @Override
    public void loadNewMarkers() {
        Notifications.Bus.notify(new Notification(Constants.PLUGIN_GROUP_DISPLAY_ID, resource.getString("Messages.Title.SuggestStarted"), "Markers generated", NotificationType.INFORMATION));
    }
});