Tax calculated for ap invoice and there is tax amount but there is not tax line in the ap invoice li

Hello,

Tax calculated for ap invoice and there is tax amount in the ap invoice general but there is not tax line in the ap invoice lines. When we have controlled zx_lines for this invoice, there are the information of it. When we have controlled ap_invoice_lines_all for this invoice, there is not "Tax" line item.

We have compared two invoices that use same tax rate code and we have saw the other invoice has "Tax" line item in invoice lines.  Why does not "Tax" line item show in the ap invoice lines?

Thanks 

There is not "Tax" line item