I have a site running ZC 1.5.8a, OPC 2.4.6 and COD payment.

When submitting an order it returns back to /checkout_one with a message "Your order's details have changed. Please review the current values and re-submit."

Console just shows

setFormSubmitButton, payment-module: cod
jquery.checkout_one.min.js?1692486216:7 Showing "confirm", paymentMethodHandlesSubmit (false)
jquery.checkout_one.min.js?1692486216:7 setFormSubmitButton, disabling Review and Confirm buttons.
jquery.checkout_one.min.js?1692486216:7 Setting orderConfirmed (0), submitter (null)
jquery.checkout_one.min.js?1692486216:7 jQuery version: 2.1.4

Any suggestions?