I just looked at the YouTube channel. I checked for updates but I appeared to already have the latest version, which says 544ccc82. Strange version numbering, If I press * on the home page, it gives me version 1.0, build 81000234.
Anyway, I can see and play from my subscriptions, as well as the one video in my Watch Later folder. Don't see any issues with it.
Nvidia Shield, Roku Stick (3600), Ultra (4640), Premiere (3920), Insignia 720p Roku TV, Sharp 4K Roku TV, Windows 10 Pro x64 running Serviio and Plex on a wired Gigabit network.