GroovyInterceptable (AOP) not working with closures

I've got a grails app with Service classes that inherit from Groovy's GroovyInterceptable:
[code]
class customerSerrvice implements GroovyInterceptable {

private List<Customer> customers

def invokeMethod(String name, args)

{ log.debug "=======>INVOKING method [$name] with args:$args" }

void foo() {
customers.each

{ doSomething(it) }
}

void doSomething(Customer cust) { log.debug "doSomething invoked with $cust" }

}

[/code]

If I call foo() or doSomething() *directly* from another class, the invokeMethod gets called like it is supposed to. However, when foo() calls doSomething(), that call is not intercepted in invokeMethod.

If I change from

`customers.each { doSomething(it) }

`

to
`for(Customer cust: customers)

{ doSomething(cust) }

`

then the invokeMethod gets called just fine.

There appears to be an ExpandoMetaClass bug that prevents closures and GroovyInterceptable from working together.