I'm not sure I like the word "deception" so much for it.

SE plays massively with levels of understanding/perceptions. Some of that is "deceptive" in the main series, in the sense that he's known all long the level of understanding of most characters and readers was very superficial and he'd go deeper as he progressed in the series - while Esslemont and him had known for a long time how things "worked".

It's only a hunch, but my feeling is those two take a similar approach to their own creation and don't consider anything to be necessarily the "final answer"m more the reflect of their own current conception/understanding of their own universe and characters. They too might keep "exploring" new, deeper layers. I haven't read Forge of Darkness yet (though I know what it's about, more or less), I'm waiting to rid myself of WOT by January at last before re reading the whole series and the few Esslemont I haven't read yet and the new Erikson, but I guess it could be in part the result of Erikson further "exploring" Drake and co. and changing his own "received ideas".

In a way their whole work is a series of "retcons". It's part of the charm of the series, it gives it a very natural, far less constructed feeling than most other Fantasy, there's something very... fluid about it all. Some of that is the result of careful planning and deep exploration of the setting and plots before Erikson even began writing, but I suspect part of even that is the result of several layers of conceptions that evolved over the years and which instead of discarding they've used in the books. Basically instead of going Tolkien's way and rewriting everything every time they changed their minds about fundamentals, they made those layers of understanding of the setting/cultures/characters an integral part of the series and they're fairly good at making it all fit with the rest. Not so much "retcons" as anthropologists finding new things that make them revise and update their own past interpretations.