I'm dealing with an old D6 Ubercart site that uses UC Coupon & UC Free Order to enable free orders for users with a certain role when they enter free order code. I'm masquerading as one these users but I'm finding it won't pick up on coupon code when I enter it. It gives me the "Warning: Coupon does not exist or is not valid." error.
I'm thinking it might be a quirk with how masquerade works. It looks like my account address book entries are showing up in Billing Information despite masquerading as another user.