This has been an issue with us for months. Roku's, Shield, PCs, tablets, phones: Netflix, Vudu, Amazon, Hulu, NowDirect, YouTube, etc... Usually the Roku Xfinity App is ok and same with Xfinity tv on the web. Odd other devices and streaming services are suffering. That being said, I have general intermittent connection issues and so could be another thing altogether. But then, why does Xfinity stuff seem ok.
kahnfewzd, I see. I'd be happy to look at your intermittent issues as well. If you send me private message with your full name and phone number, I can help.