Must click Finish twice during checkout

-- HikaShop version -- : 4.0.1
-- Joomla version -- : 3.9.1
-- PHP version -- : 7.0.2
-- Browser(s) name and version -- : CHROME
-- Error-message(debug-mod must be tuned on) -- : must click Finish twice

Hello,

User must click twice on finish during checkout to get redirected to Paypal... Shipping price is not correct then it's correct after the first click on Finish.
I read this same topic: https://www.hikashop.com/forum/checkout/886743-during-the-checkout-the-step-payment-method-must-be-clicked-twice.html
2 years old and the solution is to update and turn on "Auto submit shipping and payment methods selection" in System > Advanced
I also have "Auto select default shipping and payment methods" on Yes.

With Error Reporting, I can see this part with Warning:

$shipping_group_struct = array_combine($keys[1], $keys[2]);
		}
		foreach($this->rates as $rate) {
			if(is_int($rate->shipping_warehouse_id))

Hi,
When I deactivate the "checkout legacy", some custom dev to display a "select availability" page between "Add to cart" and "checkout page" is not working anymore.
Nevermind I will have to review the code...
Thanks.