There are 2 possible notifications when determining Wishlist Bundles settings:
1. “The Bundles is active but no level has been assigned”
This means that the “Active” option is set to “Yes”, but no levels were added in the “Level Bundles” field.
See screenshot:
2. “One of the selected levels is a bundle on his own. This bundles has been deactivated”
This means that the level “Pro” is already defined as a Bundle (Level1 + Level2), so when trying to add the Pro level to a different level (“Premium”), the plugin notifies you when you try to save the settings.