The .pmingest.dat file is an identifier that PM uses to look up in a list of identifiers for the list of files that have been ingested on that system for a given identifier. Since your two systems don't share that data, they don't know that the other system has ingested a particular set of files.
So if you never want a particular set of files to be ingested twice then you'll either have to remove the files after ingest so the second machine doesn't see them, or you'll always have to ingest on one system.
May I ask why you wouldn't want the entire set of files that are ingested to be the same on both systems?
-Kirk
As I said, I don't consider it a bug, just a minor irritation. I could format the cards more often or delete the downloaded files but, I have a inherent prejudice against doing so.
Ad for keeping the entire set on both machines... Well, the desktop had nearly 3 terabytes of backup storage attached and it has a CRT, which I find way better than any LCD screen for editing. When I ingest, I also create the file structure I use. Finally, I delete the obvious bad stuff. If on the laptop, that entire structure, original and working directories, gets copied to the desktop. If I did another ingest, I would at a minimum have to go through and delete again.
Last, I only keep really current projects and a folder of my favorites on the laptop. The desktop has a larger history that I keep on the local drive. All related to the amount of storage available on the machines.
Screwy perhaps, but it does work for me.
Jerry