An item with the same key has already been added while accessing pages in DXA

Question

Seeing the following generic issue when we access a page for the first time in DXA. Subsequent requests are able to render the content properly.

2016-07-16 00:24:24,680 [9] ERROR - Internal Server Error System.Web.HttpException (0x80004005): Internal Server Error ---> System.ArgumentException: An item with the same key has already been added. at System.Collections.Generic.Dictionary2.Insert(TKey key, TValue value, Boolean add) at DD4T.Utils.DD4TConfiguration.GetExpirationForCacheRegion(String region) at DD4T.Utils.Caching.DefaultCacheAgent.FindCacheItemPolicy(String key, Object item, String region) at DD4T.Utils.Caching.DefaultCacheAgent.Store(String key, String region, Object item, List1 dependOnTcmUris) at DD4T.Factories.PageFactory.TryFindPage(String url, IPage& page) at Sdl.Web.Tridion.Mapping.DefaultProvider.GetPage(String url, Localization localization) at Sdl.Web.Tridion.Mapping.DefaultProvider.GetPageModel(String url, Localization localization, Boolean addIncludes) at Sdl.Web.Mvc.Controllers.PageController.NotFound() at Sdl.Web.Mvc.Controllers.PageController.Page(String pageUrl) at lambda_method(Closure , ControllerBase , Object[] ) at System.Web.Mvc.ReflectedActionDescriptor.Execute(ControllerContext controllerContext, IDictionary2 parameters) at System.Web.Mvc.ControllerActionInvoker.InvokeActionMethod(ControllerContext controllerContext, ActionDescriptor actionDescriptor, IDictionary2 parameters) at System.Web.Mvc.Async.AsyncControllerActionInvoker.b__39(IAsyncResult asyncResult, ActionInvocation innerInvokeState) at System.Web.Mvc.Async.AsyncResultWrapper.WrappedAsyncResult2.CallEndDelegate(IAsyncResult asyncResult) at System.Web.Mvc.Async.AsyncControllerActionInvoker.AsyncInvocationWithFilters.<InvokeActionMethodFilterAsynchronouslyRecursive>b__3f() at System.Web.Mvc.Async.AsyncControllerActionInvoker.AsyncInvocationWithFilters.<>c__DisplayClass48.<InvokeActionMethodFilterAsynchronouslyRecursive>b__41() at System.Web.Mvc.Async.AsyncControllerActionInvoker.AsyncInvocationWithFilters.<>c__DisplayClass48.<InvokeActionMethodFilterAsynchronouslyRecursive>b__41() at System.Web.Mvc.Async.AsyncControllerActionInvoker.<>c__DisplayClass33.<BeginInvokeActionMethodWithFilters>b__32(IAsyncResult asyncResult) at System.Web.Mvc.Async.AsyncControllerActionInvoker.<>c__DisplayClass21.<>c__DisplayClass2b.<BeginInvokeAction>b__1c() at System.Web.Mvc.Async.AsyncControllerActionInvoker.<>c__DisplayClass21.<BeginInvokeAction>b__1e(IAsyncResult asyncResult) at System.Web.Mvc.Controller.<BeginExecuteCore>b__1d(IAsyncResult asyncResult, ExecuteCoreState innerState) at System.Web.Mvc.Async.AsyncResultWrapper.WrappedAsyncVoid1.CallEndDelegate(IAsyncResult asyncResult) at System.Web.Mvc.Controller.EndExecuteCore(IAsyncResult asyncResult) at System.Web.Mvc.Async.AsyncResultWrapper.WrappedAsyncVoid1.CallEndDelegate(IAsyncResult asyncResult) at System.Web.Mvc.MvcHandler.<BeginProcessRequest>b__5(IAsyncResult asyncResult, ProcessRequestState innerState) at System.Web.Mvc.Async.AsyncResultWrapper.WrappedAsyncVoid1.CallEndDelegate(IAsyncResult asyncResult) at System.Web.HttpApplication.CallHandlerExecutionStep.System.Web.HttpApplication.IExecutionStep.Execute() at System.Web.HttpApplication.ExecuteStep(IExecutionStep step, Boolean& completedSynchronously)

Where and what should be the fix for this - DD4T or in PageController.cs?