Registering components using convention doesn't seem to promote components to proxied when adding interceptors

[vengefire]

I am trying to add registrations via convention as per the following in a .Net 5 - API Project:

UserDomainManager <- IUserDomainManager <- IDomainManager

// Registration by convention instruction
container.Register(
                Classes.FromAssemblyContaining(typeof(UserDomainManager))
                    .BasedOn(typeof(IDomainManager))
                    .WithServiceDefaultInterfaces()
                    .Configure(registration => registration.Interceptors(InterceptorReference.ForKey("LogAspect"))));

// Explicit registration instruction
container.Register(Component.For<IUserDomainManager>().ImplementedBy<UserDomainManager>().LifestyleTransient().Interceptors(InterceptorReference.ForKey("LogAspect")).First);

EDIT : More detail.

The service-component pairs are being registered and injected correctly, however the backing components are not proxied and obviously the interceptor isn't called.

If I change this to an explicit registration specifying the types involved, then the proxy and interceptor functions as expected.

I'd be very happy if I was just too tired to see the obvious thing I've done wrong here with the registration, but any other ideas or suggestions would be welcome. I don't mind explicitly registering every service but I would very much like to be able to use the convention method when it was appropriate and would save time and boring boilerplate code.