"Confirm Navigation" dialogs appears randomly for almost every navigation action

Many times the (IE)
"Are you sure you want to navigate away from this page?

You have entered new data on this page. If you navigate away from this page without first saving your data, the changes will be lost.

Press OK to continue, or Cancel to stay on the current page."
shows up.

Chrome example:
Browsing issues and click to the "Administration" menu item.

IE example:
For example right after I create a new bug.

Reproducibality:
It occurs irregulary, so we can't reproduce the navigation dialog every time. It is reported by several users using chrome and IE8; so I quite confindent that it is an existing problem.

Specualtion:
I have found only error reports specific to certain scenarios in your issue database. On the net I have found some forum which claims this problem goes away after deleting the browser history of the chrome or IE. I think after clearing the history the situation is improved. It seems some undetmenistic error in connection with cokies or page cache.