AudioUnit plugin not reporting track name

Having trouble seeing the host track name changes for AudioUnit plugin. It is working okay for VST3 version of plugin. Host is Reaper.

For AudioUnit version of plugin there is a call in during initialization to

AddPropertyListener (kAudioUnitProperty_ContextName, auPropertyListenerDispatcher, this);

Which should eventully result in AudioProcessor::TrackProperties being created and relayed to the Processor once the track name is changed in the host.

However, the listener is never called. Maybe there is an extra step required for AudioUnit flavor to enable the property listener?

Any advice appreciated. Thanks!