It's just one of the little "amnesia" tricks of XP. Not a whole lot you can do about it but hope MS will fix it in some future version of Windows.
I have a particular folder I access every day and it shows; file name, size and date. About every second time I access it the date is missing. I put it back and it is ok for a while until dropping off again. This has only started recently. Can anyone assist as to why this may be?