My partner and I are having a site designed using your cart and have also noticed issues with the coupon codes.
I had first thought I encountered the exact problem that is posted here and after some further playing around with the coupon codes, I also found that when you select specific products for a coupon code to apply to, the code always saves the selections as 'all products'.
This has caused us a great amount of concern, since selecting specific products to have a sale on is a critical feature that we require.
Any idea how to fix both of these problems?