I found a work around here...

After saving, close the invoice and go to the 'Sales > Invoices'.

In the invoice list, click the invoice number.

Invoice info will pop up on the right side, click 'More actions' and choose 'Print'.

Then, there will be no 'Pay Invoice' button on the PDF.

It's still annoying than printing directly from the invoice window but I couldn't find any other...

I don't understand that Intuit cannot fix this yet even while printing here has no problem...

Maybe they don't want to fix it as they want us to use QB Pay things...

I really feel like QBO is getting stupid every time they change any.

i.e. why the Quantity fields on invoice show "1" as default every time open it, even when I saved it without any numbers on it. I have to delete them everytime. It's so annoying. And, why is the 'Quantity' changing to 'hours' in the printed invoice? What should I do to fix this...

Ted.