They probably adjust the incoming / outgoing buffer sizes (and therefore the audio delay, since it's live) to account for packet loss. They might also prioriti

They probably adjust the incoming / outgoing buffer sizes (and therefore the audio delay, since it's live) to account for packet loss. They might also prioritize traffic depending on how full your buffers are. I can only assume Youtube and Netflix do similar parameter tweaks to optimize their video delivery based on the connection (totally filling the buffer to a max size all the time would waste bandwidth, but if the client has lots of packet loss they need a larger safety net).