Assume that you use Microsoft SQL Server 2014 PowerPivot for SharePoint 2013. When the PowerPivot data refresh schedule is enabled, updated, or disabled, the following entries are no longer recorded on the data refresh history page:
The schedule was enabled by user <domain\username>
The schedule settings have been altered by user <domain\username>
The schedule was disabled by user <domain\username>
Cumulative Update information
The issue was first fixed in the following cumulative update of SQL Server.
Each new cumulative update for SQL Server contains all the hotfixes and all the security fixes that were included with the previous cumulative update. We recommend that you download and install the latest cumulative updates for SQL Server:
Microsoft has confirmed that this is a problem in the Microsoft products that are listed in the "Applies to" section.