Email alert saying Invoice Proposal overdue as per milestone even though milestone is fully invoiced

Hi guys,

I have a situation where for a project where AX shows the actual status of payment milestone as fully invoiced in the system, however, the email alert that is getting generated depicts that the invoice proposal has not been raised.

This is happening for a number of milestones for the project, even though, as mentioned earlier, fully invoiced.

What could be the cause?

Thanks for the help!