Once you have visited the reports list, the counter will no longer be shown in red (unless you have a report assigned to you). Whenever a report is updated (either a new open report or a new comment/action on an open report), the counter will be red again. This allows you to track changes to the reports. If my browser remains open, this works as above. However if I close my browser and return to the site, the reports icon is red despite the fact no changes have been made and the report is not assigned to me.