Yes!!! I did a quick search when I first started to experience it, but found no relevant hits online. Even now, yours is it for this particular problem. I hope it's a bug that can be fixed with a reinstall or update. I fear that it's Google test driving a new behavior on an account basis. tvOS is so locked down, and there is so little room for variation in hardware and software configuations on this platform, that I'm surprised more folks aren't experiencing this.
I plan to delete the app and reinstall this weekend in the hopes that it helps. I'll post here if it does.
UPDATE:
@spencecb, I'm very pleased to report that uninstalling YouTube, restarting the ATV, and reinstalling YouTube fixed the problem for me! I hope it does for you as well.