Hello there, @fghjui98765.

Allow me to share some details about this option to take out the content on the middle part of the invoice in QuickBooks Online.

This event that you've encountered isn't a bug. When customizing the invoice form, you can uncheck the information you don't want to appear. However, to make the invoice data clear to the system for future tasks, it saved the number of transactions and its amount once you're going to create it. Here are some screenshots for your reference:
 

I've added an article about setting up multiple invoice from one estimate, in case you need this on your future tasks: Set up and send progress invoices in QuickBooks Online.

I'll be here if you have other questions. Please don't hesitate to let me know in the comment section. Take care.