ERROR: 10413 - The totals of the cart item amounts do not match order amounts.

My client's website is now broken after the latest update. When a user goes to checkout, they receive the message:

Oops! An error occurred while processing your payment.
10413 - The totals of the cart item amounts do not match order amounts.

The cart worked before. Seems like every time I update, something breaks. Not cool! We need to get this resolved ASAP. I have granted support access.

Thank you.