I'm pretty conservative so I held off trying the 1.08 beta until the official release, but had an immediate issue that might be informative for anyone else who might encounter a similar problem.
I've been running 1.06 successfully in a RAID 1 configuration for over a year, using a matched pair of Hitachi HDS725050KLA360 500 GB drives at about 60% capacity.
After upgrading to the 1.08 firmware, everything looked ok at first. I was even able to install the new BT and Firefly add-ons. But about 15 minutes after restarting both front panel drive LEDs turned pink. Drive mapping stopped working, but the web UI was still operative. The add-ons were no longer listed, and the activity log said that both drives had were "removed". I reset to factory settings and rebooted. Again, everything was good for about 15 minutes, at which point both panel LEDs turned pink, and the log indicated that both drives were "removed".
I tried disabling the add-ons, etc. but each test cycle was the same: everything ok for 15 minutes, then both drives indicating they had been "removed" in the log. Eventually, I discovered a common phenomenon: the problem appeared to happen during UPnP scanning after exactly 11% of the file progress had been made. Each time the disks were automatically "removed", I checked the UPnP scan progress and it had stopped at 11%.
Fortunately, the 15 operative minutes after a reboot is enough time to re-flash back to 1.06, so I rolled back the firmware and now everything is ok again. Go figure.