I have a customer running Umbraco 4.11.10 and DAMP 2.8 but recently has been experiencing extremely long load times on the select media item dialog. In the browser console I've seen the following exception being thrown:

{"Message":"NaN is not a valid value for Int32.","StackTrace":"   at System.ComponentModel.BaseNumberConverter.ConvertFrom(ITypeDescriptorContext context, CultureInfo culture, Object value)\r\n   at System.ComponentModel.TypeConverter.ConvertFromInvariantString(String text)\r\n   at System.Web.Script.Serialization.ObjectConverter.ConvertObjectToTypeInternal(Object o, Type type, JavaScriptSerializer serializer, Boolean throwOnError, Object\u0026 convertedObject)\r\n   at System.Web.Script.Serialization.ObjectConverter.ConvertObjectToTypeMain(Object o, Type type, JavaScriptSerializer serializer, Boolean throwOnError, Object\u0026 convertedObject)\r\n   at System.Web.Script.Services.WebServiceMethodData.StrongTypeParameters(IDictionary`2 rawParams)\r\n   at System.Web.Script.Services.RestHandler.InvokeMethod(HttpContext context, WebServiceMethodData methodData, IDictionary`2 rawParams)\r\n   at System.Web.Script.Services.RestHandler.ExecuteWebServiceCall(HttpContext context, WebServiceMethodData methodData)","ExceptionType":"System.Exception"}

If logged in as an Administrator and I tick the box in the config to say ignore start node for admins the error doesn't occur. That said, the error occurs whether I have a start node selected or not without the "ignore start node for admins" option checked.

Strangely the payload for the request is as follows and shows a NaN value for start node even one is selected:

{ "nodeId": NaN, "allowedExtensions": "jpg,gif,png", "allowedMediaTypes": "1032", "cropPropertyAlias": "", "cropName": ""}

Have you come across this before? Any ideas what might be triggering it?

Thanks, Simon