Fingerprint did not match

Lately I'm getting the following entry in my log: WARNING - Connector: Fingerprint for session 'xxx' (user: [username], request info: [ip-address],Mozilla/5.0 (Windows NT 6.1) AppleWebKit/537.1 (KHTML, like Gecko) Chrome/21.0.1180.89 Safari/537.1,/,nl-NL,nl;q=0.8,en-US;q=0.6,en;q=0.4,gzip,deflate,sdch,ISO-8859-1,utf-8;q=0.7,*;q=0.3) did not match, sending 401. Can anybody explain what this means, if I should be worried, and if yes, how to avoid this?
1 answers

It means the browser fingerprint changed between requests, it could mean that someone is trying to hijack a session but there is also a bug in Google chrome frame (in internet explorer) where this can occur.