Data merge is pulling old data

I think you may have precisely hit the point when you talked about working with fresh/updated data files.

I've had a couple of clients who have recoiled in horror to find out that when they updated their reports with the "latest data" that they essentially updated all their old reports, which in turn would contain the "latest data." This was complex, because they were financial reports subject to rigid data retention requirements. Much pencil whipping and 10-K/14-K footnoting was required to explain away the issue in financial terms. 

So it wouldn't surprise me at all to find the inverse could be true. I find that many of the folks who set up automation schemes through InDesign to update company data are more familiar with setting up the database/Excel supply side of things than they are the InDesign end products that make demands of it. Understanding all the products which automate the process, then establishing rigid and consistent version controls on both the data input and report output ends of the process will likely provide solutions to the issue.

Randy