I am using the SDK Version 1.9.0 (132294) on macOS 10.15.7.
In the Simulator, if you press any key to control the d-pad or A or B buttons (for example, by pressing the arrow down or "a" key), and then switch applications (either by cmd-tab'bing, or by clicking the window of another open application), the Simulator will maintain the "down" state of the button even if the corresponding key is not held anymore.
- open the Simulator with a game
- press the arrow left key to activate the d-pad
- switch to anther application (by using cmd-tab, or clicking on the window of another Application)
- release the arrow left key
- switch back to the Simulator: the left d-pad button will indefinitely maintain its "down" state, until the left arrow key is pressed again