Description of the Issue:

When approving a price-based, invoice-attached deduction from the Deduction Workbench, the Item Sales Tax Group is not populated on the resulting free text invoice—only the Sales Tax Group is. This occurs specifically when an invoice is attached during deduction creation and does not happen if no invoice is attached. 

According to feedback on issue 1036561, the underlying reason is that Free Text Invoices are not inherently tied to the item-level data that Sales Orders use. Therefore, attaching an invoice during deduction creation does not carry over the item tax metadata to the Free Text Invoice. The deduction logic treats this scenario as a financial claim, not a product or item-based transaction, so it bypasses Item Sales Tax Group population.

Idea:

It would be valuable to reintroduce or provide the capability to select and maintain the Item Sales Tax Group on the Free Text Invoice even when an invoice is attached during the deduction approval process. This could be implemented as a dropdown or selection option that becomes available (or remains available) in the deduction approval process, ensuring the Item Sales Tax Group is not lost and avoid manual entry of the sales tax group.