Switch to the rangefinder position of the driver seat, if the gunner is aiming in any direction bar straight in front of the tank(the starting position) the actual model of the rangefinder is in the way when you look around. The camera position doesn't stay in the model so it ends up blocking the view. I've only found this on Xiangshan but I presume it will be a fault with the model.
Steps to recreate: As above, enter a Leclerc and turn the main gun to the right or left, enter the driver position and switch to the rangefinder view, you'll notice the model of the observation device blocking quite quickly.
Picture for reference:
Edit: This should probably go in the bug forum, only just noticed where I posted it, my bad.
