I think that every activity added from a backup file never overwrites existing data, so it could be a bug, really. I've take a look to the code and I cannot find (basic reviewed only) the reason for your issue.
Can you send me (privately) a copy of your (3) courses to be able to test it? And the order used to restore them, of course. This could accelerate the investigation of your issue...
TIA and ciao
Backup and restore
1.3 Restore - Maybe a Bug???
This discussion has been locked because a year has elapsed since the last post. Please start a new discussion topic.