My Fusion Drive unlinked in two pieces (SSD+HDD) and I want to restore it again in one piece
To recreate a Fusion Drive you have to delete both Logical Volume Groups and create a new one. This will delete all data on both volumes "Macintosh HD".


Booted to Recovery Mode open in the menubar Utilities > Terminal
In Terminal enter diskutil list and diskutil cs list.
Check that both disks (disk0 and disk1) are the internal disks with a size of 120 GB and 1 TB/3TB depending on your Fusion drive.
Delete both Logical Volume Groups with:

diskutil cs delete lvgUUID #with lvgUUID: the UUID of the Logical Volume Group


In your case that's: 

diskutil cs delete DD7FD...
diskutil cs delete 597C4...


Please use the complete UUIDs - I'm too lazy to write them down completely.
Rebuild the Fusion Drive with:

diskutil cs create FusionDrive disk0s2 disk1s2


This will create a new Logical Volume Group
Enter diskutil cs list to get the new lvgUUID
To create a new Logical Volume enter:

diskutil cs createVolume new_lvgUUID jhfs+ "Macintosh HD" 0g