I just installed the Discover+ channel on my Roku Ultra. Every thing appears to work ok except when I attempt to rewind a show I get a "No internet connect available" error message from the Discovery+ channel and the app freezes up. If I exit the channel and restart the program it continues to play. I am assuming this is a bug with the channel app.
Yes, most likely a channel bug. You need to advise Discovery about it, as they create and provide support for their own channels. Roku did not create the channel and cannot make any alterations to it.