Looks like Zaxcom has figured out the problem with my DEVA, and potentially the problem of many early generation units. The first of the DEVA IV and V units that were shipped with the internal DVD-RAM drive had a 2X drive. The newer media that is available for use is 3X and 5X, with higher speeds on the way. The older drives had problems with the mounting and stability of the newer media speeds. With the install of a new UJ-85J drive, the unmounting and non-responsive drive issues have gone away. I've had the drive back for 3 days now, and things seem to be very stable. I'm running version 3.39.
Let me know if you're having strange DEVA behavior, I might have some insight.