Xfinity remote and the YouTube app on tv

I can access the YouTube TV app through the Xfinity menu. I can use the Xfinity remote to select videos, play, pause, even turn the captions on and off. But I can't use the Xfinity remote to fast forward through the ads. Even when the timer showing on the bottom right appears to show that fast forwarding / skipping to the end of the ad is allowed, I can't find a button on the remote to actually do it.

I tried the Xfinity chat and the robot was not helpful at all.

Thanks for any suggestions. If I can't sort this out, I'll just have to watch YouTube on my phone if I watch it at all. I don't know why I bother paying Xfinity for television....