During document creation, the setup determines whether an existing/default customer or a newly created customer is used.
Existing Magento customer mapping → assigned BC customer
Unknown + Create Unknown Customer → new record from template
Guest → Default Guest Customer
Logged-in without creation → Default Login Customer
Bill-to and ship-to addresses are transferred separately. Verify company name, first/last name, street lines, post code, city, region, country, phone, and email.
In version 27.10.0.16, the first name may be used twice in the Sell-to Customer Name. Verify and correct the name before posting.
Guest, registered individual, company, alternate ship-to address, special characters, long fields, and missing region.
