Thank you both for your help.
Frank1940, I am running SFF-8088 to SATA cables that run to a LSI 9201-16e host card in my R610, I may take a look and see if there is some very strange situation of a power cable or something sitting too close to the cables, but by design these cables are crammed together.
trurl, that is definitely what my research led me to believe also. My original disk (WD Red 8TB) ran for quite awhile (maybe a couple years) before the CRC errors started. Sadly they continued to grow larger and larger until unraid determined that the drive was no longer valid. I will continue to watch my replacement drive and hope this was a terribly timed fluke. No other drive (3x8TB, 4x4TB) has even registered one CRC error in their years of use. This mystery of why the disk that contains "Disk 2"'s data, no matter where they are connected, are the only drives I have ever had have CRC errors will continue to elude me.
Thank you both again for your time and information.