Quote Originally Posted by Kayaker72 View Post

I have yet to come across noise being removed, unless you mean that it is minimized in modern cameras compared to before or minimized with something like faster shutterspeeds. But for the same camera, I see noise as being inherent to different processes. Now are there times when adding upstream noise by adjusting ISO better than adding noise downstream. Yes. Absolutely. That is much of the point of what astro photographers are doing and summarized in this article:
I came across a white paper from Canon that talked about the structure of the sensor. Every step in the process is designed with decreasing noise in mind. For the theory that there is no penalty the ISO Settings in camera must = the EV bar in LR.

This is a comment in your linked article:
"Upon comparison of the exposures, it’s immediately apparent that the Canon EOS 700D/T5i is not completely ISO-invariant"

This would lead me to believe that there are process in the camera that take place that are not completely replicated in LR.

Another article I was reading said that most Canon bodies are not all invariant.

This sounds like a rehash of the Sony DR argument / debate.