Hello,
I have an issue with one of my solutions. That solution only has one payment method and one shipping method, which are irrelevant and hidden to the user (in a one-step checkout). These 2 methods are available and set as default for the website's country.
If I add products to my basket and go see it in the backend, I can see that the payment and shipping method are set correctly. Once in the basket, when i complete the checkout, the order in the backend suddenly doesn't have any shipping or payment selected. It is not a big problem because this solution is 9.3.13. But I need to update to the latest 9.4 and when I do that I cannot complete the chackout because I get an error message "The payment method is not set". If I downgrade the error disappears.
I tried to have the methods displayed in the basket for testing, and it confirms my findings : when I arrive in the basket, they are shown and set correctly, but as soon as I proceed, they disappear. By that I mean that not only the ids for selected payment and shipping methods have been voided, but I cannot see these methods at all, they have disappears from the loops (which are now empty). I have tried adding a hidden field with the payment id hard-coded, but I have the same issue.
I don't have any custom code acting at that moment of the checkout process (and none which does anything to the shipping and payment methods).
Do you have any idea where that could come from ?