Tried this:
- Max on monitor 1
- simple scene with a teapot
- material editor > create corona bitmap > pick hdri > place in the Max environment slot
- start IR docked in viewport
- material editor on monitor 2 or monitor 1 (did not make any difference)
- click and drag the rotate > environment spinner in the Corona Bitmap
- observe the environment rotate in IR
Set IR upscaling factor to 1 and 2, no difference.
So I was unable to reproduce it. If you can provide more information how to reproduce it, we can investigate further.