It should be clear that InterceptionFactory.ignoreFinalMethods() only affects the generation of the "proxy" which enables interception. E.g. the following example would FAIL during validation of myFoo injection point (bootstrap):

 @Inject
 Foo myFoo;

 @Produces
 @RequestScoped // -> Requires a client proxy
 public Foo produce(InterceptionFactory<Foo> interceptionFactory) {
        // Suppose Foo has a final method
        return interceptionFactory.ignoreFinalMethods().createInterceptedInstance(new Foo());
  }

The reason is that the CDI container must treat the producer as a deployment problem (unless javax.enterprise.inject.spi.ProcessBeanAttributes.ignoreFinalMethods() is used for the producer method).

I understand that it's not very intuitive. On the other hand, these are two different concepts. I.e. the injection point validation happens during bootstrap while the InterceptionFactory is used at runtime.