I'm having the same problem. I use Illustrator on my Surface Pro (200% scaling) and a 24" monitor (100% scaling). If my Illustrator app window is on the larger screen at 100%, the bounding box uses the Surface Pro's 200% scaling factor, appearing off screen beyond the lower right corner of the artboard.
To make matters worse, dialog boxes (e.g., properties, settings, etc.) pop up on the Surface Pro screen (aka Monitor 1) at 100% (very, very tiny) even though the app window is on Monitor 2.
I'm having the same problem. I use Illustrator on my Surface Pro (200% scaling) and a 24" monitor (100% scaling). If my Illustrator app window is on the larger screen at 100%, the bounding box uses the Surface Pro's 200% scaling factor, appearing off screen beyond the lower right corner of the artboard.
To make matters worse, dialog boxes (e.g., properties, settings, etc.) pop up on the Surface Pro screen (aka Monitor 1) at 100% (very, very tiny) even though the app window is on Monitor 2.