Thanks for getting back here in the thread, @AR08. Now that I'm here. Let's work this out so you can get through this and see the additional text when receiving the emailed form from QuickBooks Desktop (QBDT).

You can run QuickBooks Tools Hub to ensure this isn't a data issue in your company file. I'll gladly input the steps below so you can proceed. To begin, download QuickBooks Tool Hub. Here's how:

1. Close QuickBooks.
2. Download the most recent version (1.4.0.0) of the QuickBooks Tool Hub. Save the file somewhere you can easily find it (like your Downloads folder or your Windows desktop). However, If you've already installed Tool Hub before, selecting the Home tab lets you find out which version you're using. The version will be displayed on the bottom right or you can select About to view the version.
3. Open the file you downloaded (QuickBooksToolHub.exe).
4. Follow the on-screen steps to install and agree to the terms and conditions.
5. After the installation, double-click the icon on your Windows desktop to open the tool hub.

If you're unable to locate the icon on your desktop, you can search for QuickBooks Tool Hub in your Windows button. 

You'll then run the Quick Fix my Program from the Tools Hub to begin repairing your program. Please be aware that this shuts down any open background processes. Here's how:

1. In the QuickBooks Tools Hub, select Program Problems.
2. Select Quick Fix my Program.
3. Start QuickBooks Desktop and open your data file.

Once done, you'll want to access the template and edit it again. You can also create a dummy invoice and then send it to yourself to see if it works. If the issue persists, you can delete and recreate the template.

In addition, I've got you this article about fixing custom email template in QBDT: Fix custom email template issues in QuickBooks Desktop.

@AR08, don't hesitate to get back to me if you need further assistance with this. You can also post here again if you have any additional QuickBooks-related concerns. I'll be more than happy to help you out again. Take care, and have a nice day!