(15984719) Coupons that were created using the Coupon Batch feature cannot be applied to the order when using Preview.
When you create coupons using Coupon Batch and then try and apply the coupons in Preview mode, when you add a product to the shopping cart, you will get a "We're sorry, this coupon cannot be applied at this time." message.

Workaround: Coupons that are created separately, and not through Coupon Batch, can be applied to an order in Preview.

(15996180) Coupons that have a Coupon Usage Limit = 1 value, are not limited to single use.
When you add a coupon that has the Coupon Usage Limit set to1, it is applied to the order. However, once the order is submitted, the coupon can be re applied to another order. This is because the coupon adds its promotion to the user’s activePromotions, however the promotion is not deleted once the coupon has been used because coupon usage is not verified in the PromotionsTool.

Reports

(13272372) Changes to user contact information are not logged if the ownerId on that record is not set.

User contact information stored in the data warehouse may not be up to date if there is no ownerId set for the user’s record at the time when changes are made.