Unityscripts with inheritance and IEnumerator functions can cause an exception once called:
[System.Runtime.InteropServices.SEHException] {System.Runtime.InteropServices.SEHException: External component has thrown an exception.
at UnityEngine.Internal.$Calli.Invoke90(Int32 arg0, Int64 arg1, IntPtr method)
at UnityEngine.MonoBehaviour.StartCoroutine_Auto(IEnumerator routine)
at Test.$onClick$1.$.MoveNext()
at UnityEngine.Internal.$MethodUtility.$Invoke85(Int64 instance, Int64* args)
at UnityEngine.Internal.$MethodUtility.InvokeMethod(Int64 instance, Int64* args, IntPtr method)} System.Runtime.InteropServices.SEHException

To reproduce:
1. Download the attached scripts
2. Import them into a new unity project
3. Add the TestSub script to the main camera
4. Build & run for WP8 (development build with the current scene)
5. Press the button. Wait for a few seconds - the text appears as it normally would, but an exception is also thrown