Because the data is "spanned," the file table (MFT or equivalent) is stretched across the disks. If Disk 2 dies, the computer no longer knows where the pieces of the files on Disk 1 or Disk 3 begin or end. Does a Universal "JBOD Repair Tool.exe" Exist?
If you are looking for a reliable executable to handle a JBOD crash, these are the industry standards: jbod repair toolsexe
JBOD Repair Tools.exe: Restoring Your "Just a Bunch of Disks" Array Because the data is "spanned," the file table