The Created vs Resolved Issues Report seems to use the Australian timezone/date formatting, as the weeks are wrong at least in a Finnish (GMT+2) system. When it is currently week 37 here, it is week 38 in Australia. In Jira (4.1) running on a Linux box in our timezone (server configured correctly), Jira shows in the report data for week 38, when this week has not begun yet and it means week 37.