I encountered a similar issue today and the "Scan Terminated" date and timestamp were accurate to the time of the event version 18.104.22.1689.
2/14/2013 12:31:41 PM Engine version = 5400.1158
2/14/2013 12:31:41 PM AntiVirus DAT version = 6985.0
2/14/2013 12:31:41 PM Number of detection signatures in EXTRA.DAT = None
2/14/2013 12:31:41 PM Names of detection signatures in EXTRA.DAT = None
2/14/2013 12:31:32 PM Scan Terminated COMPUTERNAME\SYSTEM Unable to initialize the scanning engine; the system is out of memory. Free up some memory and restart the scan application.
Due to the nature of what occured in this case was the McAfee Scan was terminated when the laptop was being shut down by the normal window shut down process, howeve during shutdown the computer because unresponsive and hung, causing the "Force shutdown" option to appear and be clicked on.
This event was not sent to McAfee EPO until the laptop was re-connected to the network the following day, which created a confusing event as the time and date between the "Detection time" and the "Reporting time" when it was reported to EPO.
Recommendation/Feature enhancement: Add a time and date field for the event for when the event was send to the management server, which will show the time the event occurred and the time the event was successfully submitted to the management server.