OK... we now believe it was a 'user error'. You're correct: E3 prints the terms description for whatever terms are specified in the order/invoice. E19 prints the code for those same terms.
Please forget what I wrote in my previous post. Adagio is doing it correctly.
We think someone must have gone back into the order or invoice and changed the terms from 'Due on delivery' back to the original terms of 'Net 30'. Apparently, someone here has a paper trail of the order actually showing 'Due on delivery'. It now reads 'Net 30'.

You're correct: The terms code is actually 'N30ROG' not the one I had originally posted.

Thanks for your help!

Andre