Hi. Just updated our site from 2.3.0 to 2.4.3, hoping this would resolve an issue with Paypal Express getting stuck in a loop between the payment page and the website order confirmation page. It didn't resolve it, the issue is intermittent and Paypal do not want to help.
One thing that we need to rule out as a cause is the Amasty shipping table rates not being passed to Paypal checkout, instead zero value shipping is passed using a label 'no_rate - £0.00 GBP'. Upon returning to Magento checkout to complete the order, the customer has to select the shipping method and 'Place Order', this often (not always) returns the customer to Paypal, again showing 'no_rate' for shipping.

Should the Amasty rates be passed to the Paypal Express checkout?
Thanks, Rob