0 Call to a member function getType() on null after PayPal Checkout payment

-- url of the page with the problem -- : www.petloc8.it/
-- HikaShop version -- : 6.5.0
-- Joomla version -- : 6.1.1
-- PHP version -- : 8.4
-- Browser(s) name and version -- : All
-- Error-message(debug-mod must be tuned on) -- : 0 Call to a member function getType() on null

Hi,
I've got 2 sites ( www.petloc8.it and www.mecs.org ) with the same error after PayPal checkout payment.
PayPal register the payment but, when the user is redirected to web site after payment, the page has the following error:
0 Call to a member function getType() on null
Thank you