The Intel RST for my Intel desktop board using desktop Seagate Barracuda drives was working without issues until I had a drive failure. The good news and bad news is that the replacement drive I used to rebuild the array has just failed a Seatools for DOS long test. It passed a short test. I had tested the three drives with Seatools for DOS when I first began investigating my parity errors. All the drives had passed all the tests.
I suspect the Intel RST verification program detects the early indications of drive problems, before they arise to the level that they can be detected by the operating system and Seatools. I noticed an Event 11, Disk error in my Event Viewer Windows Log for the System yesterday. The description indicated the driver detected a controller error on \Device\Harddisk1\DR1. The replacement disk is on SATA port 1. I ran the Seatools for DOS again and the drive failed.
I'll replace the drive when the warranty replacement arrives. The RST program hasn't kicked it out the array yet. If the parity error issue is resolved with the second replacement drive, then everything was and is working as intended.