I saw an odd event occur on several ASA upgrades. Several devices are upgraded from 8.0(4)34 to 8.2(1)11. All devices had NTP authetication configured and working. After the reloads, all context-based ASAs had lost all NTP configuration except the 'ntp server x.x.x.x key #' command. The non-context ASA kept its configuration when undergoing the same upgrade. Once the context ASAs had the relevent NTP configuration re-added, they all worked fine. No other lines of configuration appear to have been lost.
I am not sure if this is because of the fairly big jump in versions or something else but the commands are the same between versions for NTP authentication. I'd be interested in seeing if anyone else has seen similar issues.