Duplicating an activity in a course fails silently if backup_import_<foo> is disabled.

When the backup_controller constructor calls $this->apply_defaults, the "included" setting for the activity gets turned off if the relevant config setting is disabled. The controller is using "MODE_IMPORT", so this is not surprising.

The duplicate function should work correctly no matter how these settings are configured.

I suspect the best answer is to define an appropriate new mode that does not override anything.