Magento "Update Attributes" is overriding attributes

We've got a a problem using the "Update Attributes" feature of Magento Backend (see screenshot "[login to view URL]") in a Magento CE 1.9.2.4 shop. The problem is that even though I only check one of the "change" checkboxes and enter a value it will override many other attributes for the selected items. As you can see in the screenshot [login to view URL] some of the attributes in the list are "black" and not "grey" so they seem to be "active". What I can do now is to check the "change" checkbox once and uncheck it again. Now the attribute form is grey and the value will not be overridden for the selected items. So what we need is a solution which makes sure that only those attributes are touched by the "update attributes" feature which are checked by the admin and a value is entered - so standard behaviour. We'd give FTP and backend access to the dev-shop. After finding and fixing the bug we need clear information about it so we can apply fix it in the live-shop as well.