This does not happen here (WASAPI Exclusive, Event), although there is a a slight "hiccup" on resume--not a fade-in but a momentary "pop-and-resume" as opposed to an immediate resume. What audio device output selection in MB prefs are you using, and what version of MB? If you are using DirectSound, check the settings in Windows Mixer and any 3rd-party "audio panel" that may be influencing this.