Php Error On Checkout In V.4.13.3

We upgrade our CS-Cart Multivendor to 4.13.3

When we go to Checkout we get this error and more. Although sometimes at the bottom of the page we see the Checkout form.

Why is this happening and what can we do to fix it?

PHP Notice

Message

Undefined index: applies

Error at

app/functions/fn.cart.php, line: 4278

Backtrace


	
		
			File:
		
			app/functions/fn.cart.php
	
	
		
			Line:
		
			4278
	
	
		
			Function:
		
			<b>{closure}</b>
	
	
		
			File:
		
			app/controllers/frontend/checkout.php
	
	
		
			Line:
		
			615
	
	
		
			Function:
		
			<b>fn_calculate_cart_content</b>
	
	
		
			File:
		
			app/functions/fn.control.php
	
	
		
			Line:
		
			691
	
	
		
			Function:
		
			<b>include</b>
	
	
		
			File:
		
			app/functions/fn.control.php
	
	
		
			Line:
		
			434
	
	
		
			Function:
		
			<b>fn_run_controller</b>
	
	
		
			File:
		
			index.php
	
	
		
			Line:
		
			25
	
	
		
			Function:
		
			<b>fn_dispatch</b>
PHP Notice

Message

Trying to access array offset on value of type null

Error at

app/functions/fn.cart.php, line: 4278

Backtrace


	
		
			File:
		
			app/functions/fn.cart.php
	
	
		
			Line:
		
			4278
	
	
		
			Function:
		
			<b>{closure}</b>
	
	
		
			File:
		
			app/controllers/frontend/checkout.php
	
	
		
			Line:
		
			615
	
	
		
			Function:
		
			<b>fn_calculate_cart_content</b>
	
	
		
			File:
		
			app/functions/fn.control.php
	
	
		
			Line:
		
			691
	
	
		
			Function:
		
			<b>include</b>
	
	
		
			File:
		
			app/functions/fn.control.php
	
	
		
			Line:
		
			434
	
	
		
			Function:
		
			<b>fn_run_controller</b>
	
	
		
			File:
		
			index.php
	
	
		
			Line:
		
			25
	
	
		
			Function:
		
			<b>fn_dispatch</b>