The April 2014 Cumulative Update (CU) for Project 2010, Project 2013, Project Server 2010 and Project Server 2013 is now released (mostly) so see Microsoft Project Server 2010 and 2013 April 2014 CU Announcement for the full details. Due to some recent issues with SharePoint and Project Server 2013 SP1 there are some packages held back, including a patch that contains several of the fixes for Project Server 2013 that folks are waiting for. View load failures in timesheets, status update for mater pages, saving protected baselines and grouping in views are ones affected. More information once I have it.
There should be no issue installing the April CU if you already loaded SP1 (I gave a false alarm earlier – but my server had a pre-release SP1 installed). We will be re-releasing SP1 and when we do you should re-install even if you have SP1 installed already – this will ensure no issue will be seen with future patches.
*** Update 4/22 SP1 re-release
Stefan's blog has the full download links for SP1 http://blogs.technet.com/b/stefan_gossner/archive/2014/04/22/sp1-for-sharepoint-2013-has-been-rereleased.aspx
And patch again to avoid the lost resources issue - unless you also load April CU. http://support.microsoft.com/kb/2933444