Stream App Programs Not Starting On First Try

Lately whenever I try to watch a program on my Windows 11 computer using Vivaldi browser on the Xfinity Stream site, I have to initiate playback twice to get it started. This happens with live programming and with recorded programs. When I first start the playback, I get a full screen black playback window with the logo of the network or station involved, then often a message such as "Well that didn't go as planned . . ." When I go back to the grid or list of recordings and launch the same stream, it typically works. I'm not aware of any browser settings that would be affecting playback like this. Is there something I'm missing here? It's a little frustrating having to start every program twice.