I obviously didn't explain very well
The sequence of events is :

I revert to the standard module and uncomment the code in question.

I add a product that is in stock to my cart
I add a product that is out of stock to my cart
I add a product that is in stock to my cart

When I add the product which is out of stock it correctly processes i.e.
I get a header message saying "Products marked with *** are out of stock. Items not in stock will be placed on backorder."
A "***" flag appears next to the out of stock item in the cart.

When I add the next product which is in stock it processes incorrectly i.e.
I correctly get a header message saying "Products marked with *** are out of stock. Items not in stock will be placed on backorder."
Unfortunately the "***" flag no longer appears next to the out of stock item in the cart.

So I have reverted back to the "Athena Code" which processes correctly for me. I would appreciate it if some others could confirm the sequence of events on their systems for the standard module with the code uncommented as suggested by CarolineBogart, as this might be an issue specific to my system.

Quote Originally Posted by CarolineBogart View Post
jodpcc: if I understand the question, I'd quibble with the fact that it's a problem. If I'm going to change code of that nature, I'm going to also wipe cache or reset the server or something to wipe out people's carts. It's not a fair test to change the code in mid cart like that.