Hi Murali -
I'd guess that this data source does a scheduled (extract) refresh against the "original" source of data. That refresh happened late last night during your "batch window". Because the data source was refreshed, the "Modified" date updates to the last time it was changed -- last night.
Hope this helps!
Hi Russell, In the interim, I have checked even these Schedules, and none are pointing to this!
How about any log files that I can check and know little more about it?
With this the big search is on the workbooks that uses this data source and see if they are being refreshed/ published last night. It looks a big exercise until I know which data source is used by which workbook. I wish there is an easy way here other than opening the workbook and knowing which source it is using!!