delete product in cart error page with: 0 Call to a member function get() on nul

-- url of the page with the problem -- : ubuntushop.biz
-- HikaShop version -- : 6.5.2
-- Joomla version -- : latest
-- PHP version -- : 8.4
-- Error-message(debug-mod must be tuned on) -- : 0
Call to a member function get() on null

delete product in cart goes to error page with: 0 Call to a member function get() on null

errors scrrenshot attached
it happends if you click on the red x, and also when you lower the quantity to zero.

fixed, but when deleting a product in cart, the folowing page says: "no products in this category"