I can confirm this issue. I have two Roku.
The stream channels were working perfectly without this issue for over months. This starts happening about 15 weeks ago. I have reseted the router and reconfigure it. I did speed test, change router, reset youtube app and a lot more but nothing helps; therefore, it is not the network or wifi related.
this happens very randomly, sometimes, it just goes out in 5 mins, sometimes, it has no problem for 30 mins. I found this only happens for "live".Youtube version I tried:
youtube 1.0 build 8000021
youtube 1.0 build 8000284https://www.youtube.com/watch?v=6KEVEkAhMlMhttps://www.youtube.com/watch?v=4ZVUmEUFwaY