Just a little update on this. The problem seems to have taken care of itself. I got an update a few weeks ago, and now Magic Dosbox works as it should. So it seems it was a bug, either in Android, or in Samsung’s software.
I can also mention that the problem was more serious than the first post indicated. The entire interface for modifying profiles were ruined, too. If anyone has similar problems, maybe a system update is in order.