Hot air does cool according to the laws of thermodynamics, but sure ok the laws of the universe are suspended in this thermal chamber because of this mystical housing, that must be what it is protecting the part from, and it is a reflection that the OP fails to mention, why would it give a consistent reading of 85? SO this reflection is also amazingly consistent? The entire part on all sides has the same reflection? Wouldn't it or shouldn't it vary significantly based on anything that would impact the reflection? You are assuming that not only that this reflection exists, but that all of the variables that influence this reflection remain constant and unchanging because the result is unchanging. How improbable is that? You are welcome to make as many assumptions as you like but there is not reason that I must make the same assumptions or agree that your assumptions are correct.

ok well how is the camera accessing the part inside a container, inside a thermal chamber and why is a camera being used to measure temp and not a temp probe? If it is inside an oven and the question is why would one material in the oven not be the same temperature as other materials in the oven the conductivity of the materials is a logical answer especially since the material in question is a metal housing. Yes the reflection of light will influence measurements of light but there is no mention of light being reflected by the user I am assuming is familiar with the instrument they have chosen. Granted matter is limited but it surely within the realm of possibility that the metal housing is acting as heat sink. This is even more possible when the notion of moving air is added to the equation. Air moving over metal... what is the housing protecting the part from? The conditions should not be the same inside the housing as outside the housing because it would longer be a housing but just another part being heated returning me to my original point that the amount of energy required to raise the temp of the material will vary based upon the properties of the material. It just so happens that in this case known properties of the known materials suggest heat can and should be lost.

why not? Is this metal the outer layer of the system. One side at 105 the other at some other temp, such as room temp. Conduction of the material is important especially if the question is why is one thing one temp and this other thing another temp. How thick is this metal? Why would it not act as a "heat sink?" I think it applies, it is thermodynamics but the last time I thought I was wrong I was mistaken.

Heat=energy.

How much energy is required to raise the temp of silver is less than steel because one is more conductive than the other. Properties of the material being heated play a role but heat is lost over time. Assuming you are not putting any more energy (heat) into the system.