Grid Persistence Demo Broken (2015 Q2)

Unfortunately, 2015 Q2 broke our application's RadGrid Persistence behavior. Calling LoadState() in the Persistence Framework breaks and never returns (100% cpu).  The same broken behavior can also be seen on Telerik's Demo for this:

http://demos.telerik.com/aspnet-ajax/controls/examples/integration/persisting-grid-settings/defaultcs.aspx?product=grid

Note that you cannot Save and Load properly and the AJAX call will never return when clicking Load.  This is the same behavior we are experiencing in our application after upgrading to 2015.2.623.45