PARTIAL SOLUTION:
Tried everything I could think of and the only way to fix the issue was to set Vorpx HUD settings to maximum. The game treats the scope as part of the HUD, so however large the HUD is on screen is how large the scope view will be. Which means to fix this you have to play with a big HUD, which is not what I would ordinarily want, but in this circumstance it’s better than having a distorted scope view.
I guess I don’t understand why the default scope/HUD settings look fine in FULLVR view but NOT in Cinema view?