Getting Synced Metadata to Stay Synced

[Elucreh]

Having a little trouble getting my metadata syncing to stick.

I'm working with an iPad2 and Windows 8, and everything is up to date as far as I can tell; I've had this problem across a couple of different updates and computers.

I run Marvin XD and it gives me the highlighted colors just fine; I right-click and tell it to import from Marvin to Calibre. It runs just fine, finishes the job, everything is green. (By now I also always try to export the newly-imported info back into Marvin once all the titles have turned green, just to be sure exactly the same info is in both databases.)

I disconnect, I reconnect, I run XD again, and I have the same number of unmatched meta highlights as before, despite having changed nothing in either location. Am I missing a vital step?