I just ran a test import from 2.2.5 and found out it generated about 80 order notification emails... only got one sent in by a customer so far which was a backorder notification from over a year ago so I don't know what the content of the rest were, but my mail report shows a bunch sent from the default email address.
There are over 14k orders, so I'm guessing there is something in just that handful that the import choked on. Anyone else experience this or know the cause?