Xbox One X exhaust exceeding 80c and smelled of burning plastic

(To summarize only youtube is allowing my xbox to run insanely hot and not running the fan)

I read responses to other questions about heat concerns and they always stated the One X will shut down if it reaches a certain temperature but not once was it said what that temperature was. What is that temperature? From new it always blew what I thought
was extremely hot air out the back but it never exceeded 55c at the exhaust while doing nothing and the fans would kick in at that temp as needed. My xbox has always been nearly silent and maintained that temp regardless of load. I only noticed the problem
because of the smell of melting plastic and when i checked the temperature at the exhaust it was over 80c reaching near 89c if i put the thermalcouple less than an inch in to the plastic grill touching the cooler and i didn't hear the fan at all. All I was
doing was watching YouTube. It did not feel like the fan was on at all. Outside of convection there was no moving air through the system. After restarting I could finally feel the fan move a small amount of air but it was still barely doing anything and completely
inaudible.

The following is added roughly 5 hours after first typing the above.

After typing all that i decided to try a game and at 66c on the dot every time the fan would speed up and get the temp back below 66c and go back to being virtually silent. It's silent even when its ramped up at 66c but if you put your ear to it you can
actually hear it finally and definitely feel plenty of air flow. It seems the fan does not run during youtube regardless of temperature. After playing the game i put youtube back on and just let it play for another 4 or 5 hours and the exhaust again reached
nearly 80c and there was no sign of the fan doing anything. I don't know if it is a problem for everyone and they don't notice it since I tend let my xbox run youtube from morning to night even if I am not watching it and I doubt others leave their systems
playing youtube non-stop. As of now only youtube makes my system go above 66c. With an exhaust temp that is exceeding 80c i hate to think what the cpu/gpu temp was.

:)