We’ve completed an import of all our order history into Shopify. The import was made via API. A quirky thing we did and might be relevant is that we first attached a placeholder email to the order - email which was not associated with any existing customer - and then we updated the email to a real one.
Our issue is that some clients are not seeing the whole order list in the new customer account, that is, even if such orders are indexed by customer in the backoffice/API, it is not on the customer account.
Something that ca be done is to run the OrderCustomerSet mutation to force a customer set on the order but we still need to understand the underlying problem.