Recently I've found that when a customer goes to checkout and hits the
craft\commerce\controllers actionPay() using a custom gateway that it's automatically marking the cart as complete.
This never used to happen, the gateway would set the cart to complete after receiving a webhook response itself at a later time, allowing the customer to go back and update their cart before checking out properly(or not as they decide).
Now if they hit the back button they, obviously, have an empty cart as it's been marked as completed (along with the automated emails etc that are sent at that time).
Can someone point me in the right direction on how to stop this auto-complete from happening?