Hello,

by default, state is not display on the invoice so it is not a problem.

Be aware, that if we save the invoice as an attachment, it because once printed, you should be able (legacy) to print the identical invoice at anytime.... So if you have updated the customer address or the layout meanwhile, it will be no more possible.

To disable the 'PDF store' you can go in Settings -> Technical -> Report (in developer mode)

Next select your report (account.invoice in your case)

And you can change the condition when it is stored...