I saved a file to the USB drive, waited 5 minutes, and then removed the drive. When I plug it into my Windows 10 PC, it still reports that there is a problem with the drive which it offers to repair; after the repair, it is fine and the saved files are all there - it seems that the scope doesn't close out the file session after a save. This isn't a whine, it's an observation.
I don't see the triggering issue (or the USB drive observation above) as a big deal, it's sort of quirky and I could live with it as-is but if they tuned it up to fix both I'd be happier.