Basket Fails on “Cash on delivery” orders

Ok so this has taken us 2 days to discover whats happening, i’ll try and be as details as possible, we have setup a dummy version so you can play around in a test environment

So our Woocommerce has 2 payment options, 1 sage and 1 “cash on delivery, renamed “pay on account”

If you order and pay using Sage credit card, everything works fine. But when a customer users “cash on delivery (renamed Pay on account)” the order fails to complete, it brings up a blank woocommerce error, the order does get placed but the customer gets no email and isn’t told, so they click over and over again.

Now we managed to drill down, and it is related to the TAX function, payment method and your customiser, reason being, we have a VAT switcher, which if we remove the TAX switcher the customised email works, so you may think its the VAT switcher.

But

If we put the VAT switcher back on, turn the customiser off and use the default WordPress emails, it works

So there is some sort of TAX corruption between the way VAT (tax) and your customiser creates emails