Error count not incremented
Guardian tries to count the number of times a given user-agent has experienced a server error. This number will be displayed in the email report and also in the log data. For example:
The error was caused by a visitor from: j3021.inktomi.com This visitor has caused a 404 error 8 time(s).
The error count is maintained with a session cookie. It will not be incremented under the following conditions:
If the user-agent does not support cookies, then the ErrorCount will always be 1. Some web browsers can be configured to not support cookies, and also most robots and probes do not support cookies.
If Guardian responds with an "http-redirect" rule, the ErrorCount will usually not be incremented, since user-agents choose not to honor Set-Cookie headers in a redirect response.
Whenever the user-agent process exits (i.e. a user closes all instances of his browser) then all session cookies are expired. Subsequent visits will start with ErrorCount 1.
"Error count not incremented" https://www.xav.com/scripts/guardian/help/1011.html