“MediaTek PreLoader USB VCOM port” or “MediaTek USB Port”?

How the mobile phone (that is off) informs the Windows PC (with installed drivers “MediaTek PreLoader USB VCOM port” and “MediaTek USB Port”) how to identify itself: as device – “MediaTek PreLoader USB VCOM port” or as – “MediaTek USB Port”?

I don’t see any system – when I plug the phone to PnP PC, Windows connect it sometime through “preloader”, sometimes through “regular” ports, sometimes both in sequence (I see it from WMI events).