Odd lines in cogserver.log before crash

[cfunkho]

Our Cognos 10.1 BI Server crashed last night.  In the cogserver.log, there are thousands of entries like these leading up to the crash (brackets indicate where I've replaced info for this post):

[server ip]:9300   12572   2014-04-22 18:03:02.957   -5   [hash]   [hash]         http-9300-22   CM   6235   3   Audit.Other.cms.CM   QUERY   ACCOUNT   /[AD directory]/[user]    Success   

The entries are for the same four users (including myself) over and over again, like it keeps checking those logins against the AD server.  After a restart, those types entries appear occasionally in the logs, but only at what appear to be appropriate times (such as checking the credentials for a login being used to run a recurring event).

Any idea what might cause this?

Thanks,
Chris Funkhouser