Amount posting to inventory in error

I am having a coding issue when I post a bill from suppliers for raw material/inventory.

To illustrate, the supplier bill in question is for $20,000 plus GST, total $21,000.  

Given the above example, I would expect the following journal entry:

Debit Inventory:                                $20,000

Debit GST paid on purchases/ITC   $1,000

        Credit Accounts payable                       $21,000

The above entry does post in the GL, however there are a couple of extra lines posting with the entry that are causing the inventory costing to be incorrect.  The following entry is what is actually posting:

Debit Inventory:                                $20,000

Debit GST paid on purchases/ITC   $1,000

Debit inventory:                                 $6851.32

         Credit COGS                                           $6,851.32

         Credit Accounts Payable                         $21,000
                           

Is anyone else seeing this?  I have run the rebuild and verify utility multiple times, and nothing has changed.