Thanks for reaching out to the community for your concern, @ksottile.

For me to be able to provide you with an appropriate solution, I'd like to know if you tried to create an invoice for an item with a warranty. Or perhaps a product was returned by a customer within the warranty period. Any additional information will be much appreciated.

I'll be in the comment section for your response and for any other invoice and QuickBooks-related queries you'd like to bring up. Take care.