This has been an issue plaguing me for a long time as well.
I use multiplicty mainly for multiboxing in a mmo. The game sound has never cut out. But if I am watching Twitch on a pc that shares audio to the main it will cut out all the time. Was hoping the patch/update a while back would help but it has not.
It's never consistent either, it makes me wonder if the differences in streamer set ups/bitrates etc can have an effect on it. Unchecking "Enable audio sharing" on the sending pc the sound will start coming through that pc speaker, then when checked again will work as intended, for a random period of time (I've had it go out seconds after, or minutes).
I've never lost mouse control, and all pcs are wired directly to the network, no wireless
I have uninstalled cleaned and did a reinstall in the past, have lurked many of these discussions.
One thing that might help, I have 3 box pcs, one is older running Windows 7sp1. It never drops audio. The two others are Windows 10.
Edit: Well this post got my brain working this am and I started comparing settings between the 7 and 10 machine.
7 was using 16bit, 44100hz, 10 was 24bit, 48000hz.
Lowered 10 machine to 16bit, 44100hz.. and the audio has stopped cutting out. Hopefully you guys can figure out why.