It is possible. It could also be your hardware raid controller.
What I can't tell is how you have configured this. You say you have software RAID1 on top of hardware RAID0. I can't quite tell what your config looks like though. What disks are in the each RAID0 and how have you configured the RAID1. Have you got say disks a,b, and c in RAID0 set A and then d,e, and f in RAID0 set B and then you RAID1 sets A & B?
I have 4 discs: disc 0, 1, 2 & 3. In the RAID controller disc 0 & 2 are in RAID0 and 1 & 3 are in RAID0. Then i installed SME in RAID1 mode ontop of the two sets.
I wanted to run hardware RAID 1+0, but it didn't seem like this was possible in the RAID controller, so stupid me figured that it was ok to configure the discs to run hardware RAID0 and software (SME) RAID1. When i installed the SME i ran it with the option RAID=1: "SME RAID=1"
So now it's probably better for me to either run hardware RAID5 or software (SME) RAID5.