"A fix was released for all versions of Google Chrome on Wednesday, September 22. Chrome users were automatically updated to version 6.0.472.63 over the last few days," he announced.
Webmasters saw an unusually high visitors count while page views saw a big drop. The bug was active during September 7 and September 22 and affected Google Chrome 6.0.472.55 and up. The latest update to the stable channel, Chrome 6.0.472.63 fixed the issue.
However, sites may not have been affected during that entire period, it depends on what version Chrome users were running when visiting the site. Even though Chrome has a silent update system, which installs new versions within days of their availability, some users may have not updated in that time.
By now, most users should have updated to Google Chrome 6.0472.63 which includes the fix so analytics data should be reported correctly now.