diff --git a/make_post_sell/views/cart.py b/make_post_sell/views/cart.py
index d3a23b2..7eaf968 100644
--- a/make_post_sell/views/cart.py
+++ b/make_post_sell/views/cart.py
@@ -1069,6 +1069,13 @@ def paypal_complete_checkout(request):
                 continue
 
         if successful_invoices:
+            # MPS-20 + MPS-21: flip linked auction/offer state BEFORE
+            # the cart_offers / cart_auctions get touched downstream.
+            # Without this, a PayPal- or Adyen-paid negotiated cart
+            # leaves the offer stuck in ACCEPTED and the UI keeps
+            # showing Pay/Cancel even though the invoice is settled.
+            _finalize_auction_offer_state(cart, request)
+
             for invoice in successful_invoices:
                 for line_item in invoice.line_items:
                     cart.remove_product(line_item.product, line_item.quantity)
@@ -1304,6 +1311,13 @@ def adyen_complete_checkout(request):
                 continue
 
         if successful_invoices:
+            # MPS-20 + MPS-21: flip linked auction/offer state BEFORE
+            # the cart_offers / cart_auctions get touched downstream.
+            # Without this, a PayPal- or Adyen-paid negotiated cart
+            # leaves the offer stuck in ACCEPTED and the UI keeps
+            # showing Pay/Cancel even though the invoice is settled.
+            _finalize_auction_offer_state(cart, request)
+
             for invoice in successful_invoices:
                 for line_item in invoice.line_items:
                     cart.remove_product(line_item.product, line_item.quantity)