I have a shopping cart rule that is set up so that any user (guest or otherwise) can use a coupon code to get 30% off their shopping cart.
We don't want this discount to apply to shipping, so we've set 'Apply to Shipping Amount' to 'No'
However, I'm finding that some of our customers are receiving 30% off shipping as well.
This seems to be an intermittent issue - I.e. sometimes the discount is applied to shipping, and sometimes it is not.
What can I do to debug this issue?
It is worth noting that this is the only shopping cart/catalog price rule we have set up on the whole website.
Any help is appreciated.