System.ArgumentException when flipview adds to m_postsLists

[QuinnDamerell]

I am going to add code to work around this for now, but this is a problem. I don't know what's causing it because I can't repo it. :(

Stack:
System.Collections.ObjectModel.ObservableCollection<System.Object>.OnCollectionChanged(Collections.Specialized.NotifyCollectionChangedEventArgs e)
System.Collections.ObjectModel.ObservableCollection<System.Object>.InsertItem(Int32 index, Object item)
System.Collections.ObjectModel.Collection<System.Object>.Add(Object item)
Baconit.Panels.FlipViewPanel.<>c__DisplayClass29_0.b__0()