VS2013 linq FirstOrDefault bug getting Index out of range

I'm attempting to join 2 dbsets (Transactions, Departments) as a way to filter for a specific entity (Transaction) such as:

var result = (from x in context.Transactions
                           from y in context.Departments
                           where x.Location == y.Location&& x.Location == Location &&
                           x.Department == y.DeptId &&
                           y.Org == OrgId &&
                           y.DeptInactiveDate == null &&
                           x.InactiveDate == null
                           select x).FirstOrDefault();

I've tested the SQL generated by this code and it returns the proper data (and I can see it executed successfully via the context in the output window), however;  FirstOrDefault() always triggers a System.ArgumentOutOfRangeException in mscorlib.dll specifically:

This code previously worked in VS2010 + EF4.1 but doesn't work in VS2013 + EF6