We have 2 item receipt forms. One (CF A) is marked as preferred in the custom form itself. The other custom form (CF B) is marked as preferred and restricted to Role A (in the custom form and role record). When I log in using Role A, it still makes use of CF A. Any reason why?

If you look at the purchase order form there is a tab called linked forms. Is CF A the linked form to the custom PO form you are using on your purchase order?

Ohh yeah it is. So the linked form prevails over the preferred form per role.