Hi all, it does seem that Quickbooks in their infinite knowledge and updates has further downgraded their site. I was able to find a solution by using an older version of the Quickbooks mobile app (version 27.42.0). It still let me go into an invoice and set it as flat rate, it still looks a little wonky on the website but the pdf view shows it being what I want. Screenshots attached.
I would suggest not updating the Quickbooks mobile app if you haven't already. Hopefully they don't start version verifying to make us endure their awful changes they constantly make. My old invoices don't seem affected either, hopefully that stays that way too. I'll be sending in negative feedback about this change and I suggest you all do too
