Question / Help Inconsistent Audio NDI Source

[mvalente429]

In a recent video I did with my brother via Skype, I noticed the audio levels of my brother's feed (via NDI) fluctuates between when we in on screen by himself and when we have a split screen. Any reason as to why this happens?

https://www.youtube.com/watch?v=ulUQSD0ggaY&feature=youtu.be