I am trying to toggle between two different invoice templates when creating new invoices and the invoice isn't changing. Why?

Thank you for posting in the Community, Mike.

When you create a customized template for your printed invoice, you can choose which fields to include that are appropriate for your business. If there is unusual behavior on your account despite not having made any changes, it could be due to your browser storing too much cache. 

You can access your QBO account using a private browser window, which ignores cookies and doesn't save browsing history. To open a private browser, use these shortcut keys on your keyboard:

• Safari: Control + Option + P
• Google Chrome: Press Ctrl + Shift + N
• Firefox or Internet Explorer: Ctrl + Shift + P

If this works, it means that you need to clear the browser's cache so the system can start fresh. If you get the same result, I recommend switching to a different supported browser.

In addition, feel free to check this article for future reference if you want to personalize your reports: Customize reports in QuickBooks Online.

Please don't hesitate to post if you have any further questions regarding customizing invoices or any other QuickBooks-related matters. I'm always here to assist you. Take care.