Express Checkout - Smart Buttons fail when item is already in cart.

[angelleye]

• http://fiber.angelleye.com/temp/smart-buttons-fail.mp4

[angelleye]

Seems this must be related to #1016. When I view the EC log after this happens I see this:

2018-03-23T05:51:58+00:00 INFO Array
(
   [error] => Array
       (
           [0] => <a href="https://www.angelleye.com/cart/" class="button wc-forward">View cart</a> You cannot add another "PayPal for WooCommerce Multi-Account Management" to your cart.
       )

)

The option to prevent adding an additional item is not enabled in my settings, though. I tried enabling it and saving settings, then disabling and saving again, but that didn't help.