Cache expiration with format not working as expected

Hi all,

In my OrdersController, I have two actions completed and incomplete
that respond_to HTML and CSV.

Im also action caching these actions

..
caches_action :completed, :incomplete
...
def completed
   @orders = Order.completed
   respond_to do |format|
      format.html
      format.csv {render :layout => false}
   end
end

def incomplete
  @orders = Order.incomplete
   respond_to do |format|
      format.html
      format.csv {render :layout => false}
   end
end

Now the cached fragments when I go to the CSV urls are

views/localhost:3001/orders/completed.csv
views/localhost:3001/orders/incomplete.csv

My sweepers have the following cache expiration commands
..
expire_action :controller => :orders, :action => :completed, :format
=> :csv
expire_action :controller => :orders, :action => :incomplete, :format
=> :csv
...

But the log says

Expired fragment : views/localhost:3001/completed.csv
Expired fragment : views/localhost:3001/incomplete.csv

notice that it missed "/orders" in there? The cache therefore never
expires for the CSV format output. It works fine for HTML though. Any
idea what im doing wrong?