A forgetful filesystem

We have this laptop running Open SuSE 10.1 installed on a ReiserFS. Recently all of a sudden a file - and a hidden file nonetheless - reverted to the contents it used to have at least several months prior. It being a hidden "dot" file makes it highly doubtful the owner modified it by mistake.

I am, quite obviously, a bit surprised here... The only explaination that comes to mind is that ReiserFS being a journaled filesystem, it for some reason rewound the journal. Now why it would do it - I have no clue. If you know the secret feel free to use the comments to enlighten yours truly and the others in the dark.