Hello,
It seems that the Fake pointer support when no mouse pointer is attached doesn't work correctly with a Bluetooth mouse, at least not the Apple Magic Mouse 2.
When the option is enabled, it leaves a ghosted copy of the mouse pointer that follows the primary mouse pointer around. Spent a few hours digging into researching this, only to find Multiplicity was the culprit.
See option I'm referring to and a video that shows the problematic behavior. I want to use this option as the Bluetooth mouse is not always on. It should see a mouse detected and not use the fake pointer.
Video Link