Hi,
I don't think there is anything we can do about this new issue you're talking about.
From what you're saying I think that this is what is happening:
You're using a payment plugin for the newebpay payment gateway. I suppose you're using the plugin available for HikaShop and developed by Newebpay themselves, and available on this page :
www.newebpay.com/website/Page/content/download_api#2
So I took the liberty of downloading the plugin and having a look at its code.
There, I found this line:
'shipping_address' => $this->_getAddress(isset($order_info->cart->shipping_address) ? $order_info->cart->shipping_address : $order_info->shipping_address),
That's the line which provides the shipping address of the order to the payment gateway.
I suppose that because the order doesn't have a shipping address when using the shipping address override, the payment gateway switch to 3DS mode where credit card verification is mandatory to ensure it is a legit transaction.
Changing this line to :
'shipping_address' => $this->_getAddress(isset($order_info->cart->shipping_address) ? $order_info->cart->shipping_address : $order_info->billing_address),
in the code of the plugin in order to provide the billing address when the shipping address of the order is not available will probably make it work like you want.
A better solution would be to add an extra check so that when the shipping address is missing in the order, and if the shipping address override is activated for the shipping method selected for the order, it would switch to the billing address. But if the override is not activated and the shipping address is missing, it would keep not providing an address so that the payment gateway doesn't need to switch to 3DS when the shipping address is overridden.
I think that's a feedback which needs to be brought up to the tech support of your payment gateway.