Welcome to the QuickBooks Community, and thank you for taking to time seek out our help. Earlier in this thread, I posted some troubleshooting steps to help with resolving this issue. Have you had a chance to verify your terms are set properly, or try the data damage troubleshooting? If you have already, or once you have the opportunity, post here once more with what your end results are. Should you still have trouble after performing what I've recommended, please include screenshots of the affected terms and their set up; this will help me to determine what to try next
It's my priority to get this resolved, so don't hesitate to ask any additional questions about this or anything else QuickBooks. In the event you would like to be rid of the past due stamp on your invoices, you can remove the mark entirely from your forms by following this article here: Show Past Due stamp on invoices.
Note: look under the section titled "Turn off the Past Due stamp".
As I mentioned before, should you need anything else, you can find me right here in the community. I look forward to hearing from you!