3759290 - Unable to edit the "Alternative tax classification" field at the sales order - SAP S/4HANA Cloud Public Edition

Unable to edit “Alternative Tax Classification” manually at the sales order header level, even though the value is maintained for the tax condition type in the "Maintain Tax Relevance for Customers" configuration activity.

SAP S/4HANA Cloud Public Edition

1. Go to the sales order header.
2. Enter a value (for example, “Z”) in the "Alternative Tax Classification" field.
3. Continue or save the sales order.
4. Observe that the entered value is cleared.

One possible reason is that an empty or incomplete implementation of BAdI SD_SLS_MODIFY_HEAD_TAX lacks essential data transfer logic, which causes the tax classification fields to be cleared.

Review the BAdI SD_SLS_MODIFY_HEAD_TAX. Ensure the BAdI implementation is correct — if there is no custom logic, make sure the mandatory lines are still present, as this code prevents accidental data clearing.

* First, copy the values from the tax-relevant fields to the output parameter. * If you use developer extensibility and multiple implementations, embed this code in an if statement. *

* if salesdocument_tax_out is initial.
* salesdocument_tax_out = salesdocument_tax_in.
* endif. 

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