The results with a file GDB were mixed, so I did some additional testing this morning. Originally, to get the data into the Pro default GDB, I exported from the map. But to put the data into a new FGDB, I used import. I also used import to put it into SDE. (By the way, I'm copying entire feature classes, not features to existing feature classes.) So, I wondered if the different results were due to export vs. import?
This morning, I created a new FGDB. Then, in ArcCatalog, I exported from SDE to file GDB. When I publish from the new FGDB, everything shows up. Then I exported from the SDE to a different SDE. That publishes fine, too. Maybe there's something else uncontrolled that I'm overlooking, but for now I'd say that export and import aren't exactly reverse operations. I'll stick to export.