Inconsistent behaviour re. Shopping Cart Edit QTY and PRICE fields

Hi,

Using R12.1.3, and testing RPC5 patches.

This is the version of the /oracle/apps/icx/por/req/webui/ShoppingCartPG page on non RPC5 instances:

And on RPC5 instances:

This is a simple Non Catalogue REQ item I am adding to the cart:

I have tested it on non RPC5 instance, and RPC5 instance:

PROD - QTY can be changed:

TEST instance, RPC5 applied - QTY and PRICE can be changed for USERA:

TEST instance, RPC5 applied - neither can be changed for USERB:

I can't work out why the form behaves differently for different users on the same instance, and even between instances, on one you can edit the QTY, on another, for 1 user, you can edit both, for another user, you can edit none.