Well, I've had the chance to try a series of different 980 Pro drives and would you know it...same problem. RAID 5
So, my "not-so-expert" opinion currently, is that: a) backups are a must (of course); b) my board (chipset likely) is faulty/has some issue; c) don't trust your data to these new boards; d) it is still probably a good idea to run some sort of RAID configuration for data storage because at the very least, it can rebuild (backups are still a must).
Unfortunately, I'm really very disappointed with ASUS for this current generation. I've pretty much insisted on using ASUS boards for all my builds (and any builds I do for others) and this is honestly, the most problematic build I've ever had.