TransactionServices and after completion issue

I'm currently implementing a solution to leverage the transactional event facilities of CDI in Java SE.

I've implemented:

• A TransactionServices class and made sure it's loaded via the ServiceLoader
• A UserTransaction class
• A Transactional interceptor

And I have added the weld-jta module to my project.

Everything is fine until I invoke afterCompletion() of the synchronization observer.

Test conditions:

    private void onInit(@Observes @Initialized(ApplicationScoped.class) Object event) {
        Schedulers.single().scheduleDirect(this::fireEvent, 1, TimeUnit.SECONDS);
    }

    @Transactional
    public void fireEvent() {
        LOGGER.info("firing event");
        events.fire("hello");
        LOGGER.info("event fired");
    }

    @Transactional
    private void onEvent(@Observes(during = TransactionPhase.AFTER_SUCCESS) String event) {
        LOGGER.info(() -> String.format("event received after success: %s", event));
    }

Please note that the Transactional annotation in the example above is my interceptor binding annotation, not the JTA's one.

When afterCompletion is invoked, the transaction related to 'fireEvent' is committed. A new transaction is started when the observer method is invoked.
When the observer method returns, the later transaction (related to 'onEvent') is committed. But then, a new event is fired again and it's value is null, and in the logs I can see:

InfraUserTransaction - begin new transaction
TransactionTest - firing event
TransactionTest - event fired
InfraUserTransaction - committing transaction
InfraUserTransaction - transaction committed
InfraUserTransaction - notifying after completion - STATUS_COMMITTED
InfraUserTransaction - begin new transaction
TransactionTest - event received after success: hello
InfraUserTransaction - committing transaction
InfraUserTransaction - transaction committed
InfraUserTransaction - notifying after completion - STATUS_COMMITTED
ERROR Event - WELD-000401: Failure while notifying an observer [BackedAnnotatedMethod] private steappe.production.application.TransactionTest.onEvent(@Observes String) of event null.
java.lang.IllegalAccessError: tried to access method steappe.production.application.TransactionTest.onEvent(Ljava/lang/String;)V from class steappe.production.application.TransactionTest$Proxy$_$$_WeldSubclass
InfraUserTransaction - after completion notified
InfraUserTransaction - after completion notified

As you can see, the list of events to distribute after the completion of the first commit seems to contain some remaining of the first distributed event. Then, after the second commit, WELD tries to distribute this event again.

I had a look to the source code of weld-jta, and I can see that:

• The synchronization observer is set when an event is fired
• The synchronization observer is not cleared when a new transaction is started while an AFTER_SUCCESS event is being notified

I had a look to the CDI specifications, and I could not see anything that would explain the reason why this code should not work.

Did I misunderstand the specifications? Did I do something wrong? Or is there a bug?