I have been curious about same thing. For me the difference between each ITT is not that much big but there is difference for sure. In my case difference is 8 to 15 degrees.
And I found it might be a sort of solutions for that.
1. Adjust both engines oil amount full position (not amount of oil. it's sensor )
2. When you start engines, don't start fixed side. Sometimes start from left, sometimes from right.
3. After the flight, sometimes you need to make the aircraft cold and dark state and leave it for 20mins give or take to make engines cool.
If you want to ignore this situation, make a new profile.
I'm not sure that is kind of a bug or realistic behavior of the aircraft but on the other hand it's fun to seek how to avoid this kind of situation.