PO not getting approved

Hi,

We have a Purchase Order which is auto-generated from a non-catalogue requisition and has an associated Contract Purchase Agreement. The buyer for the PO then logs in and 'Approves' the PO. This buyer has the requisite authority to incur etc however the PO remains in an unapproved status. The action history displays:

A Buyer | SUBMIT

A Buyer | NO ACTION

It is only when the PO is Approved and Forwarded to someone else (also with authority) that the PO's status is updated to 'Approved', and APPROVE is logged as the action_code in the action history table.

Has anyone else noted this behaviour?