We aren't doing anything with subscriptions, so that may be related somehow, but probably isn't the cause. We have also tested the following themes which all experience the issue. Origin, Craft, Dawn, and Refresh themes. 

On our checkout, when you click the tip button it makes a background post to update the cart, the response for that post returns 2 errors:TIP_ONLY_EMPTY_TERMS_ACCEPTED   "This policy only accepts empty terms."PAYMENTS_UNACCEPTABLE_PAYMENT_AMOUNT  The...