Thanks for coming back for more support, @Yachties.

Since the issue persists even after following my peer's suggested fix, I'd recommend contacting our Customer Care team. That way, we can take a closer look at the issue through a screen sharing session and help you fix it. 

Here's an article that you can visit to learn more about customising invoices and sales Forms in QuickBooks Online. 

Feel free to post your concerns again. I'd be delighted to help.