I am having the following issue with an email template that has me stumped, I have stripped out all the other info to get it to work with one field. When I enter the has_content on the payment terms it works, but when I use the same format on the PO number it fails

it looks like you're typing freemarker into the non-code view of the template... maybe try clicking the "Div" icon in the top left and re-entering your values, then saving.