Hi there, MrRidley.
To investigate this issue, I suggest contacting our Phone Support Team so they can open an investigation as this is similar to our international version where Tax Reg is auto populated on Custom Invoice Templates. This way, you'll be be added to the notification list for updates.
Here's how to contact them:
1. Open your QuickBooks Account.
2. At the top right, click the Help icon.
3. Click Contact Us.
4. Under What can we help you with?, enter any concerns.
5. Click Let's Talk.
6. You'll be routed into the Choose a way to connect with us page.
7. Select how you want to contact them and fill in the information.
Please check this article on how to personalize your form designs and add the info that matters to your business: Email and customize sales form.
Please know that you're always welcome to post if you have any other concerns. Wishing you and your business continued success.