Can anyone here tell me what 'Updating' means in the adstar logs?

While running adstar in a Unix (Solaris) environment,
we occasionally get the following log entry:

10/23/1995 19:10:46 Updating-->     768 /FILENAME  Sent
                     ^^^^^^
Thousands of other files, which seem to be the same type,
are logged one of these two ways:

10/25/1995 21:20:07 Expiring-->    1,761 /FILENAME  Sent
10/25/1995 21:20:07 Normal File--> 4,159 /FILENAME  Sent

We assume it is some administrative nuance, because the files
are backed up seemingly the same as all the others.
But what exactly does 'Updating' mean?

Art Sulger
New York Department of Health
Unix Systems Administration