This happens because Moonlight sends your keyboard input to the host PC.
#IfWinActive, Moonlight !Tab::return ; Disable Alt+Tab while Moonlight is active alt tab moonlight
The most effective solution is to run the host game in (or "Fullscreen Windowed") mode. This happens because Moonlight sends your keyboard input
In the Moonlight settings menu, look for the option. look for the option.