When you go on the AA eshopping site and click on the alphabetical list of merchants to get to the merchant of your choice, there may be a list of valid coupons that you can use. If you just click on the merchant's logo gizmo on AA eshopping from the home page screen, you will not see the coupon opportunities that will not spoil your AA miles earning.
If you use another coupon source especially from an email, likely you will not get your AA miles.
Be careful!