I have enabled zero subtotal checkout in Magento 2.1.5 and now I have a problem with the place order button being disabled if a user tries to place an order on the checkout page, if an order with a value over zero is in the cart then the button is enabled, I have tested with 2 different themes with both the same problem.
I'm not sure what code would help diagnose this issue so please let me know
Any ideas?
