I recommend you disconnecting and reconnecting the drives from the motherboard. After that, please check the SATA ports where these drives are connected are enabled at the BIOS level.
If issue persists, I would strongly recommend you saving the information and trying to restart the volume.
Did you find a way around this? I just ran into the same issue after an attempted bios update. Everything looks proper in the bios, which I rolled back to. I have a lot of data and 2 out of the 3 drives are saying they aren't raid drives. I checked the board and bios multiple times. I have very little confidence in this RAID controller at the moment.
So this is a VERY common problem and caused me to lose lots of data. Shame on you intel for not having better tools for this. I missed a step in the process so my data is GONE. A bios reset/upgrade should not be an issue that causes this.