When a bad block is discovered in a particular disk the bad block is then remapped within the remapping pool and is stored across multiple disks. I would contact the RAID manufacture and ask to assist you on a deeper investigation. Please back up your data!
I would start with the basics and run the memtest and then the file system repair utility - if you are using NAS.
Memtest is done by rebooting the system and after POST hit the ESC or TAB key there you will see the basic menu - run the memtest for at least 45 min. If now errors then reboot and go to the Console screen and enter CTRL + ALT + X then run the File repair option.
Only do this if you are absolutely sure your RAID set is good!