Yes, a failing drive can very well cause this behavior. If you are getting S.M.A.R.T. errors, then there is definitely something wrong with the drive. I can't be certain if it is the cause of your problem, but chances are very good that it is. To see if it's that drive, take it out of the RAID array, then disconnect it's data and power cables. (Contact Intel support if you need help with this.)
S.M.A.R.T. keeps track of certain parameters (e.g., spin up time, number of bad sectors) and monitors them for abnormal changes to predict imminent failure. It's not that accurate in that hard drives often fail with no S.M.A.R.T. errors being reported and some hard drives that do report S.M.A.R.T. errors can still run just fine for years, but I would not use a hard drive reporting errors for any important data. If it is under warranty, then having S.M.A.R.T. errors is enough to get it replaced, even if it has not failed yet.