PO Approver not updating

In R12 - updates to PO Approver descriptive flexfield is not saving.

Navigation - Purchasing > Supply Base > Suppliers (web page opens):

1. Enter in Supplier Name

2. Address Book

3. Manage Sites

4. Descriptive Flexfields

I have a descriptive flexfield called PO Approver - I am able to select a valid PO Approver, I click Apply and it takes me back to the Manage Sites screen (from here if I click on Descriptive Flexfields again the PO Approver is still populated).  If I click on Apply from the Manage Sites screen and I'm taken back to the Address Book screen - when I click on Manage Sites > Descriptive Flexfields again the PO Approver is blank.