Enabling the TraceBrokerPathPlugin with a custom property name = 'JMSXTrace' sends outdated information to the consumer. When inspecting the property at the consumer code, it has not been updated with the complete broker path. Only the first broker, where the message was produced into, appears. No matter how many brokers are in the route (tested with 4).
Having dug into the code, it looks like marshalledProperties in Message were already set but not dirtied when setProperty was called again from the TraceBrokerPathPlugin. Also, Message.beforeMarshall() assumes that since marshalledProperties is already set, it doesn't need updating. Therefore, the message is dispatched to the consumer with an old version of the properties.
I think Message.setProperty() should check whether marshalledProperties already has a value. If it does, it should re-marshall (i.e. dirty the cache).