Tax is not calculate on particular PO line

Dear Experts,

We are encountering an unexpected issue while attempting to save the purchase order, as we have observed that the tax is not being calculated for a specific line item. It is important to note that tax should be applied to each line. In an effort to resolve this issue, we have tested the following workaround; however, we did not achieve the desired result.

Workaround

Delete the item line where tax is not calculated and re generate another new item line for same item but afterwards still tax is not calculated on PO.