I gotta agree, using the Man 'O' War with anything is sorta a wonky process with my experience.
Do you have Razer Synapse? Sometimes Synapse likes to hijack the audio for itself so you gotta make sure it's linked and everything.
If you don't have synapse, I'd look at your playback devices before and after your headphones turn on and off. It tends to do wonky things (Especially if you use Voicemeeter or other speakers) like stealing the default audio output and such.