Problem on application startup?

Question

I have an application on Asp.net mvc 5 hosted on a dedicated server and in some moments when the Application Pool is unused and the IIS raises it on the first access I’m getting the following error:

System.ArgumentException: Source array was not long enough. Check srcIndex and length, and the array's lower bounds.
   at System.Array.Copy(Array sourceArray, Int32 sourceIndex, Array destinationArray, Int32 destinationIndex, Int32 length, Boolean reliable)
   at System.Array.Copy(Array sourceArray, Int32 sourceIndex, Array destinationArray, Int32 destinationIndex, Int32 length)
   at System.Collections.Generic.List`1.set_Capacity(Int32 value)
   at System.Collections.Generic.List`1.EnsureCapacity(Int32 min)
   at System.Collections.Generic.List`1.InsertRange(Int32 index, IEnumerable`1 collection)
   at System.Collections.Generic.List`1.AddRange(IEnumerable`1 collection)
   at NHibernate.Event.EventListeners.InitializeListeners(Configuration cfg, Object[] list)
   at NHibernate.Event.EventListeners.InitializeListeners(Configuration cfg)
   at NHibernate.Cfg.Configuration.BuildSessionFactory()

The problem of this error that it does not occur frequently is once or twice and it is very difficult to figure out how to solve it, when this error happens while restarting the Application Pool it stops happening.