i also have this isuue with z390 strix im not sure what its detecting ive just got used to it, have you got anything logitech?
If you use keyboard/mouse with configurable macro, in order to be able to assign macros globally, accessory manufacturers such as Logitech install virtual devices visible via your Device Manager > Human Interface Devices (example for Logitech : Logitech G HUB Virtual Keyboard/Mouse).
If this (new hardware sound) really bothers you and you don't use macro, you can uninstall these virtual devices (but they will likely be reinstalled the next time you update or uninstall/install your device manufacturer's software).
but your keyboard supports macros? like mochiku said it sounds like its the virtual mouse or keyboard that comes with certain devices, go in device manager and do you see anything "virtual" under human interface devices
btw if you find a fix for this please message me