It appears there is a known issue related to Purchase Order Invoice postings where there is a zero dollar posting being included in the Invoice voucher. 

MS Support team suggested i create an "Idea" for this issue so that the MS product team would consider fixing this issue in future releases.

Issue Definition:

Purchase Order Invoice, Zero Dollar Posting for Purchase Expenditure for Product.

Scope Agreement:

Once we are able to investigate and help with the issue in the invoiced purchase order having zero dollar posting for the purchase expenditure for product, we will consider the scope to be met.

Findings:

• Created a new Purchase Order.

• Confirmed and Received the Purchase Order.

• Done the Invoicing to the Purchase Order.

• Checked the Invoiced Journal, the “Purchase expenditure for product” is 0.00 USD.