Created Unassigned: Exception type: OperationCanceledException Exception message: Script entries not loaded yet. [27572]

Exception is thrown in latest release 4.5.7.1005 when __doPostBack is called from javascript in Release mode. But if you set your site to Debug mode, no issues

Event code: 3005
Event message: An unhandled exception has occurred.
Event time: 11/17/2013 4:56:12 PM
Event time (UTC): 11/18/2013 12:56:12 AM
Event ID: 4fb8094368dc4f35a02efb1410433093
Event sequence: 11
Event occurrence: 1
Event detail code: 0

Application information:
Application domain: /LM/W3SVC/5/ROOT-13-130292091614732049
Trust level: Full
Application Virtual Path: /
Application Path: X:\Apps\Viaway\111613\Portal2\
Machine name: VS01_VIAWAY2012

Process information:
Process ID: 9476
Process name: w3wp.exe
Account name: IIS APPPOOL\Site

Exception information:
Exception type: OperationCanceledException
Exception message: Script entries not loaded yet.
at AjaxControlToolkit.ToolkitScriptManagerCombiner.IsScriptRegistered(ScriptReference scriptReference)
at AjaxControlToolkit.ToolkitScriptManager.OnResolveScriptReference(ScriptReferenceEventArgs e)
at System.Web.UI.ScriptManager.RegisterScripts()
at System.Web.UI.ScriptManager.OnPagePreRenderComplete(Object sender, EventArgs e)
at System.Web.UI.Page.ProcessRequestMain(Boolean includeStagesBeforeAsyncPoint, Boolean includeStagesAfterAsyncPoint)



Thread information:
Thread ID: 71
Thread account name: IIS APPPOOL\Site
Is impersonating: False
Stack trace: at AjaxControlToolkit.ToolkitScriptManagerCombiner.IsScriptRegistered(ScriptReference scriptReference)
at AjaxControlToolkit.ToolkitScriptManager.OnResolveScriptReference(ScriptReferenceEventArgs e)
at System.Web.UI.ScriptManager.RegisterScripts()
at System.Web.UI.ScriptManager.OnPagePreRenderComplete(Object sender, EventArgs e)
at System.Web.UI.Page.ProcessRequestMain(Boolean includeStagesBeforeAsyncPoint, Boolean includeStagesAfterAsyncPoint)


Custom event details: