Strange entry in the Log.nsf - Databases view

Just noticed this curious entry in the Log File, Usage By Size view. All the database documents have entries along the following lines:

Title: Wanted & For Sale

File Name: saleWant.nsf

File Size: 86.5 Mbytes (0.00% of this space is used)

Server: HUB/SVR/wwcorp

Time: 23/09 05:00:35

My Question is, does anyone know why the space used is shown as 0%? This is the case for every database on the server. It also shows this in the view - they all show as 0% used.