How do I Serialize a List of gameobjects without getting 3 duplicates/copies of each entry?

Unity 4, UnitySerializer.
My game and saves and loads fine, but some of my lists end up three times longer after reloading with the same data repeating - seems to be only when they are List<> containing GameObjects.

If I save and reload, each time the lists will triple.
I had to add a check to strip out the dulicates but I don’t think it is a good idea because the save files are larger than they need to be (I assume anyway, I can’t read the byte saved file).

One answer is to upgrade to Unity 5 and use unityserializer-ng which has fixed that issue.