Thanks for getting back to us, @Maple1.
Allow me to step in for a moment and help make sure that the notes in your items will show on your invoices in QuickBooks Desktop (QBDT).
I've also tried it on my end, but I wasn't able to see the notes either. Just to make sure that I can provide you with the best resolution, may I know how you set up or added those notes in your items? A screenshot would also be very helpful.
Just in case, you can also check out this article for future reference: Add, edit, and delete items.
I'm looking forward to your response. Take care and have a great rest of the day!