Downgrade while live stream

[edwinp2011]

I using same camera and same 2500bits when streaming but suddenly my camera downgrade when i live stream

Good one : https://www.youtube.com/watch?v=EMaNKLFmCVI&t=26s (360p)
Bad one : https://www.youtube.com/watch?v=TQDJyA9E0Ew&t=1725s (360p)

Anyone knew why ?