Using a Service class like this:

@Interceptors(MyInterceptor.class)
public class TestService {
...
}

@ManagedBean
public class MyInterceptor {
Object field;
@AroundConstruct
    public void wrapConstructor(InvocationContext ctx) throws Exception {
         field = new Object();
}
 @AroundInvoke
    public Object guard(final InvocationContext context) throws Exception {
        assert field != null;
}
}

I would expect the assert to pass. However it fails, because weld creates two instances of this interceptor, one for each Interception Type.

I did not see this documented, and I am not sure if it is a bug. If not, more documentation would help.

JSR 318 seems to say this:
http://download.oracle.com/otndocs/jcp/interceptors-1_2-mrel2-spec/
"Except as noted below, when the target instance is created, a corresponding interceptor instance is created for each associated interceptor class."

"The applicability of a method-level interceptor to more than one method of an associated target class does not affect the relationship between the interceptor instance and the target class—only a single instance of the interceptor class is created per target class instance"