The thing is that the compass position is not updated explicitly when a map is rotated.
- If the compass wasn't moved manually before the rotation, it gets repositioned automatically. In most cases it looks like it is rotated along with the map, but sometimes it is moved somewhere else. This is not a bug, however I'll probably change this behaviour.
- If the compass was moved manually before the rotation, it remains exactly at the the same unrotated position. If the map is not square, the compass may even disappear completely, and this needs to be fixed.