I haven't read it but that would completely contradict the grimoire which shows they were created. Super advanced, human like architecture, sure, but not that they were ever human.
I'd be interested to read it regardless. Link?
English
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They were created, then the copy of an existing human mind transferred to the machine frame. The human body dies but their consciousness lives on. http://www.destinypedia.com/Cayde's_Treasure_Island_Book
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Exos were created but their consciousness comes from human mind to keep great talent and great mind alive after human body is unable to carry it.