I’m trying to display the contents of a rich text field on our PDF, but when I try to save I get the error “The reference to entity “rlz” must end with the ‘;’ delimiter.” — anyone had this before?

If I remember correctly, this usually indicates a parsing error related to reserved XML characters in your template such as "&".

The only thing I’m changing is the field reference in the template. I can reference other fields on that same entity but when I change it to the rich text field it won’t even let me save the template

Are you able to share the code in question?

This is the template. It saves fine if I change the field at the bottom Does not work (this is a rich text field):

<td>${record.custbody_bottom_left_message.custrecord_message_invoice</td>

Does work (this is long text):

<td>${record.custbody_bottom_left_message.custrecord_invoice_long_text</td>

Found this from NetSuite:

I would think the error then would occur when I went to print, not when I’m saving the template

Yeah, I'm not sure about that one, but it looks like rich text fields don't necessarily work well with the Advanced PDF rendering engine.