Serializer.Resume() not working for multiple levels

So I've been using @whydoidoit Serializer to save my game.

I've been using LevelSerializer.Checkpoint() and LevelSerializer.Resume() to save the data, until I tried it on another scene.

It works perfectly on my first level, but when I use LevelSerializer.Resume() on another level, it loads the start of the first level.

e.g.

 function Update () {
 
 if (Input.GetKeyDown(KeyCode.S)) {
     print ("savethis");
     LevelSerializer.Checkpoint();
 }
 
 if (Input.GetKeyDown(KeyCode.L)) {
     print ("loadthis");
     LevelSerializer.Resume();
 }
 
 }

I've tried...

 LevelSerializer.LoadSavedLevel(LevelSerializer.SerializeLevel());
 &
 LevelSerializer.SerializeLevel();

...and all it appears to do is take me back to the start of that loaded level. Any help will be appreciated.

Thanks!