You use the Report Designer and Report Builder (SSRS) in Cumulative Update 3 for Microsoft SQL Server 2012 Service Pack 2 (SP2) or a later update.
You have a report that contains a tablix data region.
In this scenario, when the report is rendered either in print preview or as a PDF, you find that the first row of the tablix data region is expanded vertically, and the format of the rest of the tablix data region is corrupted. Note This issue also occurs in SQL Server 2014.
This problem is caused by a regression in SSRS in Cumulative Update 3 for SQL Server 2012 SP2.
Cumulative Update information
This issue was first fixed in the following cumulative update of SQL Server:
Recommendation: Install the latest cumulative update for 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. Check out the latest cumulative updates for SQL Server: