Sorry, I should have been clearer. The two SD cards do not have the same images. They also do not have the same filenames. I ingest from one card, which works fine. I then ingest from the second card, which works fine. The SD cards both end up being mounted as the same drive (d:\)
Next day, when I ingest another set of images, there is a significant likelihood that the images from the day before will be ingested again, as duplicates.