I just tried the "fast fix" and got a log text with the following error message:
Tipo: Exception
Condition: KeyNotFoundException: The given key was not present in the dictionary.
StackTrace: System.Collections.Generic.Dictionary`2[System.Int32,UnityEngine.AssetBundle].get_Item (Int32 key)
GameController+<PreLoadImages>c__Iterator7.MoveNext ()
UnityEngine.SetupCoroutine.InvokeMoveNext (IEnumerator enumerator, IntPtr returnValueAddress)
UnityEngine.MonoBehaviour:StartCoroutine(IEnumerator)
<Start>c__AnonStoreyB:<>m__1(Boolean)
<LoadGameGraph>c__AnonStorey1A:<>m__0(String)
<GetGameGraph>c__Iterator1:MoveNext()
UnityEngine.SetupCoroutine:InvokeMoveNext(IEnumerator, IntPtr)
System.tackTrace: at GameController.LogCallback(System.String condition, System.String stackTrace, LogType type)
at UnityEngine.Application.CallLogCallback(System.String logString, System.String stackTrace, LogType type, Boolean invokedOnMainThread)
at UnityEngine.MonoBehaviour.StartCoroutine_Auto_Internal(IEnumerator )
at UnityEngine.MonoBehaviour.StartCoroutine(IEnumerator routine)
at GameController+<Start>c__AnonStoreyB.<>m__1(Boolean IsOK)
at GameController+<LoadGameGraph>c__Iterator5+<LoadGameGraph>c__AnonStorey1A.<>m__0(System.String got)
at Commons+<GetGameGraph>c__Iterator1.MoveNext()
at UnityEngine.SetupCoroutine.InvokeMoveNext(IEnumerator enumerator, IntPtr returnValueAddress)