Ultimate Special Offers relies on movement from the cart page to the checkout in order to properly apply discounts. When PayPal is used on the cart page, customers are bypassing the Shopify checkout, preventing discounts from applying properly.
You can disable PayPal and other dynamic checkout buttons in the Theme editor or you can reach out to our App Support team for assistance.
Customers will still be able to pay with PayPal when they reach the checkout page.