Solved by @c.poupin in https://forum.dynamobim.com/t/sort-elements-in-a-list/53520/11:
Its a bug. 
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c.poupinDynamo Challenge Runner-up
Hello,
It’s an inheritance issue in IronPython and PythonNet (fixed for both in future versions)
see this article
[Dynamo += Python] Obtenir le nom de certains Eléments
Blog sur le BIM, du Python et d’la Dynamo appliqués aux électrons
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