Sweet times J old times I’d be angry when I see something like this but now I smile a lot .. OMG this is not ending J
Ok so what is it…
In SharePoint Central Administration there is a rule that says “Database has large amounts of unused space” with of course the “Auto Repair” function -> Don’t repair this error!
So what happens is it will start a timer-job that will shrink the database, causing fragmentation; as explained in this TechNet article: http://technet.microsoft.com/en-us/library/hh564121.aspx
So just ignore it J … or [just to be specific] shrink if you have to.