The same for me, and I've used Firefox for a long time now.
I wonder if it's some buggy FF addon causing it, and one way to find out if they keep reappearing is to disable all addons/themes then enable them one by one to see if it's caused by a particular addon/theme.
And from a Google search this is about the only topic that discusses those corrupt files. Possibly bug report it to Mozilla too.
I wonder if it's some buggy FF addon causing it, and one way to find out if they keep reappearing is to disable all addons/themes then enable them one by one to see if it's caused by a particular addon/theme.
You could all post your extensions here and see if there's an extension or two common between all three of you