Okay, fantastic! That works now. After getting it to work, I realized that I was trying to pass the $payment_id back instead of the full $payment then querying the meta data with the id. That’s really what it came down to.
This line is what tipped me off to my mistake.
https://github.com/WordImpress/Give-Snippet-Library/blob/a7b5f1f7424e1e62bdf0bcac8d92d6d78575e6cb/customized-templates/add-receipt-row.php#L15
Thanks so much!
