Am I missing something, or is there no way to turn off the grey background for list item labels (numbers, bullets, etc.)? Although the gray highlighting is handy for keeping track of list items, it is not attractive for final documents.
But since I see the grey background in the 2.5 final release notes, I am assuming that this can't be changed.
It might be that you need to uncheck "Highlight automatic numbers" in Preferences (under the General tab). Try that and see if it fixes the problem. You might need to change the view (Draft to Page or Page to Draft) to get the change to show up.