As of 11/13/2024 this is STILL an ongoing issue with QB.  When using the "Projects" feature, email addresses from the Client profile does NOT populate correctly regardless of what you do, how you format the email address or update the most current past invoice.   

This "bug" is causing our Clients to not receive invoices and this is a very basic feature of such accounting software.

I too spent 2 hours sharing my screen with level 1-2 and 3 and they all recognized the problem but advised me that there is nothing wrong with the software since I can manually enter email addresses as I create each Client invoice....YES....enter email addresses manually....why then use QuickBooks software???

Fix this problem or I take my company to another service and sure many feel the same way...this is significant "bug" in the system that is not be addresses so if you utilize "Projects" for your business....DO NOT THINK OF USING QUICKBOOKS UNTIL THIS EVER GETS RESOLVED.