Im trying to complete an order through the dwapi on 9.13.2, and we're getting this error.
here are the steps to recreate it:
create the cart: https://svsshop.websrv01.smartpage.dk/dwapi/ecommerce/carts?CurrencyCode=DKK&CountryCode=DK&LanguageId=LANG1
We haven't been able to test on 9.13.3 since you can't access cart after adding a product atm (but you already fixed that for next ecommerce nuget release)
EDIT: i just tested on 9.13.3 by getting a cart via the dwapi on 9.13.2, and then rebuilding on 9.13.3 and then trying to use the /createorder endpoint, and it results in the same error.
Hope you can help us out.