SortedList<Gameobject,whatever> Bug

Just run the scene and press the button (the one without a number in the middle).
It adds the other 3 buttons in sequence(order doesn't matter).
1st SortedList.Add(Gameobject_1,x) --> OK.
2nd SortedList.Add(Gameobject_2,x) -->InvalidOperationException:
Operation is not valid due to the current state of the object(you see no error on console cause i catch it)

Can someone confirm if this happens on Windows as well (and on other Linux as well as on other versions in both)?
IF so find the diff in code from windows and fix.(this goes to unity guys)
Unity v5.3.5f1