[CentOS] Two partitions with samd UUID??

I seem to have partitions on two different disks with the same UUID: [tim@helen ~]$ sudo blkid /dev/sda2 /dev/sda2: LABEL="/boot1" UUID="5bbc8e95-6108-41f5-bc0e-5b5f8df5ce03" TYPE="ext3" [tim@helen ~]$ sudo blkid /dev/sdb2 /dev/sdb2: LABEL="/boot1" UUID="5bbc8e95-6108-41f5-bc0e-5b5f8df5ce03" TYPE="ext3" This is causing some confusion, as these are boot partitions, and grub2 seems to be choosing the wrong one.

I wonder how this occurred; I thought different partitions on different disks necessarily had different UUIDs?

Maybe I used dd at some point. Would this keep the same UUID?