My understanding is that the Unique Identifier is a sequence of numbers saved by the Operating System to tell one disk apart from another one.
Have you tried to use a different installation media for the Operating System? The reason I asked is that you have tried this with the RAID controller and with the onboard RAID solutions with identical results.
Not sure if you have tried to install the Operating System in different sets of hard drives. For instance, if you have been installing the Operating System in the 240GB SSDs, could you try a different set like the 480GB SSDs drives instead.