Mine did that until I enabled AHCI. It's been fine since.
Turning on AHCI first meant that none of the drives worked: there's another thing that had to be done first (I forget what it was). Once I'd gone to AHCI, there was no way back (fortunately, none was needed).
The only niggle nowadays is that every so often a partition will misbehave and I'll get a message that Drive 7 Section 27 (or some such words, I forget the exact) has done something wrong. I've not found any way of identifying which hard drive or which partition letter it is.
It's been a lot better since I installed the SSD as boot drive. It's a lot faster, and most of the hiccups I used to get don't happen. At first, the SSD wouldn't "appear" on switch-on. That turned out to be something obscure to do with timing: the fix was a power delay to the SSD - it gets its volts a second after power-up and all is well.