Shipping instruction is not flowing on order line

Summary:

When I create a sales order, the Shipping Instruction is automatically populated at the header level by an extension that fetches the value from the customer master. However, when the extension populates the Shipping Instruction on the header, the order lines are marked as overridden, and the Shipping Instruction from the header does not cascade to the line level.

Content (please ensure you mask any confidential information):

Version (include the version you are using, if applicable):

Code Snippet (add any code snippets that support your topic, if applicable):