Windows Media Server staging disk activities

Hi,

We have a Windows Media Server running Netbackup 7.5. There is a staging disk configured in the server using an external storage (HDS). The activities of the staging disk is 100% view in HDS started from around 18:30hrs every Sat to Sun around 11 + hrs. We have checked the backup schedule of all the policies and cleaning schedule of the staging disk and can't find any schedule fall in that period. Any pointer is very much appreciated.

Thanks in advance.