When a second monitor is connected (with the desktop extended to it) and mouse tracking is enabled in NVDA, mouse tracking reports as if the mouse was moving up and down the edge of the first monitor - as if it was on the very far left, right, top or bottom, depending on the location of the second monitor. Playing audio coordinates seems to confirm this.

Preferred behaviour: Correctly track mouse location on multiple monitors, just as it is tracked on the first monitor.