I try defrag the drive C:
How did you start JkDefrag? By default JkDefrag will process all the mounted, writable, fixed volumes on your computer. It will also process volumes that are mounted on a subdirectory, not only volumes that are mounted on a drive letter.
but after five hours I see, JKDefrag works in the "C:\Backup" (which is not phisically in the partition C:)
Yes, after finishing with the C: volume it will process your "C:\Backup" volume. It all sounds normal to me, no bug. Please note that it is technically impossible for JkDefrag to move a file to another volume, files can only be moved within the same volume.
I see chaos in the JKDefrag graphic.
Perhaps you think it is chaos because you are expecting to see the diskmap of the C: harddisk? But you are seeing the diskmap of your "C:\Backup" harddisk.