We are developing modules for DNN 8 using jQuery.ajax calls to WebApi methods. To speed up response time we are committing several ajax calls in parallel. However, occasionally only the first call is successful and the rest are failing.

The problem is that the server exception is not occurring in our code, or in any DNN dll.
This is the exception from the Event Viewer:

Exception information: 
    Exception type: NullReferenceException 
    Exception message: Object reference not set to an instance of an object.
   at System.RuntimeTypeHandle.GetTypeByName(String name, Boolean throw , Boolean ignoreCase, Boolean reflectionOnly, StackCrawlMarkHandle stackMark, IntPtr pPrivHostBinder, Boolean loadTypeFromPartialName, ObjectHandleOnStack type)
   at System.RuntimeTypeHandle.GetTypeByName(String name, Boolean throw , Boolean ignoreCase, Boolean reflectionOnly, StackCrawlMark& stackMark, IntPtr pPrivHostBinder, Boolean loadTypeFromPartialName)
   at System.RuntimeType.GetType(String typeName, Boolean throw , Boolean ignoreCase, Boolean reflectionOnly, StackCrawlMark& stackMark)
   at System.Type.GetType(String typeName, Boolean throw , Boolean ignoreCase)
   at System.Web.Compilation.BuildManager.GetType(String typeName, Boolean throw , Boolean ignoreCase)
   at ClientDependency.Core.Module.ClientDependencyModule.LoadFilterTypes()
   at System.Web.HttpApplication.InitModulesCommon()
   at System.Web.HttpApplication.InitInternal(HttpContext context, HttpApplicationState state, MethodInfo[] handlers)
   at System.Web.HttpApplicationFactory.GetNormalApplicationInstance(HttpContext context)
   at System.Web.HttpRuntime.ProcessRequestNotificationPrivate(IIS7WorkerRequest wr, HttpContext context)

We get the same error on different machines and with both DNN version 8.0.1 and 8.0.2. The problem seems to increase with the amount of concurrent users.

Anyone?